Initial checkin for library version bounds

Code changes to provide versioning support when adding to the enumerated defines for H5F_libver_t.

24 files changed, 539 insertions, 325 deletions

diff --git a/src/H5Aint.c b/src/H5Aint.c
index 160c7fb..bfc69ec 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -112,6 +112,13 @@ static herr_t H5A__attr_sort_table(H5A_attr_table_t *atable, H5_index_t idx_type
 /* Local Variables */
 /*******************/
 
+/* Format version bounds for attribute */
+static const unsigned H5O_attr_ver_bounds[] = {
+    H5O_ATTR_VERSION_1,         /* H5F_LIBVER_EARLIEST */
+    H5O_ATTR_VERSION_3,         /* H5F_LIBVER_V18 */
+    H5O_ATTR_VERSION_LATEST     /* H5F_LIBVER_LATEST */
+};
+
 typedef H5A_t*	H5A_t_ptr;
 H5FL_SEQ_DEFINE(H5A_t_ptr);
 
@@ -210,17 +217,15 @@ H5A_create(const H5G_loc_t *loc, const char *name, const H5T_t *type,
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "invalid datatype location")
 
     /* Set the latest format for datatype, if requested */
-    if(H5F_USE_LATEST_FLAGS(loc->oloc->file, H5F_LATEST_DATATYPE))
-        if(H5T_set_latest_version(attr->shared->dt) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of datatype")
+    if(H5T_set_version(loc->oloc->file, attr->shared->dt) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set version of datatype")
 
     /* Copy the dataspace for the attribute */
     attr->shared->ds = H5S_copy(space, FALSE, TRUE);
 
-    /* Set the latest format for dataspace, if requested */
-    if(H5F_USE_LATEST_FLAGS(loc->oloc->file, H5F_LATEST_DATASPACE))
-        if(H5S_set_latest_version(attr->shared->ds) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of dataspace")
+    /* Set the version for dataspace */
+    if(H5S_set_version(loc->oloc->file, attr->shared->ds) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set version of dataspace")
 
     /* Copy the object header information */
     if(H5O_loc_copy(&(attr->oloc), loc->oloc, H5_COPY_DEEP) < 0)
@@ -1840,11 +1845,11 @@ done:
  * Function:    H5A_set_version
  *
  * Purpose:     Sets the correct version to encode attribute with.
- *              Chooses the oldest version possible, unless the "use the
- *              latest format" flag is set.
+ *              Chooses the oldest version possible, unless the
+ *              file's low bound indicates otherwise.
  *
- * Return:	Success:        Non-negative
- *		Failure:	Negative
+ * Return:	Success:    Non-negative
+ *          Failure:    Negative
  *
  * Programmer:  Quincey Koziol
  *              koziol@hdfgroup.org
@@ -1857,7 +1862,7 @@ H5A_set_version(const H5F_t *f, H5A_t *attr)
 {
     hbool_t type_shared, space_shared;  /* Flags to indicate that shared messages are used for this attribute */
     hbool_t use_latest_format;          /* Flag indicating the latest attribute version support is enabled */
-    herr_t ret_value = SUCCEED;   /* Return value */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
@@ -1865,9 +1870,6 @@ H5A_set_version(const H5F_t *f, H5A_t *attr)
     HDassert(f);
     HDassert(attr);
 
-    /* Get the file's 'use the latest attribute version support' flag */
-    use_latest_format = H5F_USE_LATEST_FLAGS(f, H5F_LATEST_ATTRIBUTE);
-
     /* Check whether datatype and dataspace are shared */
     if(H5O_msg_is_shared(H5O_DTYPE_ID, attr->shared->dt) > 0)
         type_shared = TRUE;
@@ -1880,15 +1882,19 @@ H5A_set_version(const H5F_t *f, H5A_t *attr)
         space_shared = FALSE;
 
     /* Check which version to encode attribute with */
-    if(use_latest_format)
-        attr->shared->version = H5O_ATTR_VERSION_LATEST;      /* Write out latest attribute version */
-    else if(attr->shared->encoding != H5T_CSET_ASCII)
+    if(attr->shared->encoding != H5T_CSET_ASCII)
         attr->shared->version = H5O_ATTR_VERSION_3;   /* Write version which includes the character encoding */
     else if(type_shared || space_shared)
         attr->shared->version = H5O_ATTR_VERSION_2;   /* Write out version with flag for indicating shared datatype or dataspace */
     else
         attr->shared->version = H5O_ATTR_VERSION_1;   /* Write out basic version */
 
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    attr->shared->version = MAX(attr->shared->version, (uint8_t)H5O_attr_ver_bounds[H5F_LOW_BOUND(f)]);
+
+    /* File bound check */
+    if(attr->shared->version > H5O_attr_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_ATTR, H5E_BADRANGE, FAIL, "attribute version out of bounds")
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5A_set_version() */
diff --git a/src/H5Dint.c b/src/H5Dint.c
index bdedd1e..9ed7d71 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -639,13 +639,13 @@ done:
  * Function:	H5D__init_type
  *
  * Purpose:	Copy a datatype for a dataset's use, performing all the
- *              necessary adjustments, etc.
+ *          necessary adjustments, etc.
  *
  * Return:	Success:    SUCCEED
- *		Failure:    FAIL
+ *	        Failure:    FAIL
  *
  * Programmer:	Quincey Koziol
- *		Thursday, June 24, 2004
+ *	            Thursday, June 24, 2004
  *
  *-------------------------------------------------------------------------
  */
@@ -654,7 +654,7 @@ H5D__init_type(H5F_t *file, const H5D_t *dset, hid_t type_id, const H5T_t *type)
 {
     htri_t relocatable;                 /* Flag whether the type is relocatable */
     htri_t immutable;                   /* Flag whether the type is immutable */
-    hbool_t use_latest_format;          /* Flag indicating the 'latest datatype version support' is enabled */
+    hbool_t use_v18_latest_format;      /* Flag indicating the 'latest datatype version support' is enabled */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -672,17 +672,16 @@ H5D__init_type(H5F_t *file, const H5D_t *dset, hid_t type_id, const H5T_t *type)
     if((immutable = H5T_is_immutable(type)) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "can't check datatype?")
 
-    /* Get the file's 'use the latest datatype version support' flag */
-    use_latest_format = H5F_USE_LATEST_FLAGS(file, H5F_LATEST_DATATYPE);
+    use_v18_latest_format = (H5F_LOW_BOUND(file) >= H5F_LIBVER_V18);
 
     /* Copy the datatype if it's a custom datatype or if it'll change when it's location is changed */
-    if(!immutable || relocatable || use_latest_format) {
+    if(!immutable || relocatable || use_v18_latest_format) {
         /* Copy datatype for dataset */
         if((dset->shared->type = H5T_copy(type, H5T_COPY_ALL)) == NULL)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy datatype")
 
-	/* Convert a datatype (if committed) to a transient type if the committed datatype's file
-	   location is different from the file location where the dataset will be created */
+        /* Convert a datatype (if committed) to a transient type if the committed datatype's file
+           location is different from the file location where the dataset will be created */
         if(H5T_convert_committed_datatype(dset->shared->type, file) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't get shared datatype info")
 
@@ -690,14 +689,12 @@ H5D__init_type(H5F_t *file, const H5D_t *dset, hid_t type_id, const H5T_t *type)
         if(H5T_set_loc(dset->shared->type, file, H5T_LOC_DISK) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't set datatype location")
 
-        /* Set the latest format, if requested */
-        if(use_latest_format)
-            if(H5T_set_latest_version(dset->shared->type) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
+       if(H5T_set_version(file, dset->shared->type) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set version of datatype")
 
         /* Get a datatype ID for the dataset's datatype */
-	if((dset->shared->type_id = H5I_register(H5I_DATATYPE, dset->shared->type, FALSE)) < 0)
-	    HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "unable to register type")
+        if((dset->shared->type_id = H5I_register(H5I_DATATYPE, dset->shared->type, FALSE)) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "unable to register type")
     } /* end if */
     /* Not a custom datatype, just use it directly */
     else {
@@ -775,7 +772,6 @@ done:
 static herr_t
 H5D__init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space)
 {
-    hbool_t use_latest_format;          /* Flag indicating the 'latest dataspace version support' is enabled */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -785,9 +781,6 @@ H5D__init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space)
     HDassert(dset);
     HDassert(space);
 
-    /* Get the file's 'use the latest dataspace version support' flag */
-    use_latest_format = H5F_USE_LATEST_FLAGS(file, H5F_LATEST_DATASPACE);
-
     /* Copy dataspace for dataset */
     if(NULL == (dset->shared->space = H5S_copy(space, FALSE, TRUE)))
         HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy dataspace")
@@ -796,10 +789,9 @@ H5D__init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space)
     if(H5D__cache_dataspace_info(dset) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't cache dataspace info")
 
-    /* Set the latest format, if requested */
-    if(use_latest_format)
-        if(H5S_set_latest_version(dset->shared->space) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
+    /* Set the version for dataspace */
+    if(H5S_set_version(file, dset->shared->space) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
 
     /* Set the dataset's dataspace to 'all' selection */
     if(H5S_select_all(dset->shared->space, TRUE) < 0)
@@ -926,7 +918,7 @@ H5D__update_oh_info(H5F_t *file, hid_t dxpl_id, H5D_t *dset, hid_t dapl_id)
 
     /* If there is valid information for the old fill value struct, add it */
     /* (only if we aren't trying to write the 'latest fill message version support') */
-    if(fill_prop->buf && !(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_FILL_MSG))) {
+    if(fill_prop->buf && (H5F_LOW_BOUND(file) < H5F_LIBVER_V18)) {
         H5O_fill_t old_fill_prop;       /* Copy of fill value property, for writing as "old" fill value */
 
         /* Shallow copy the fill value property */
@@ -981,7 +973,7 @@ H5D__update_oh_info(H5F_t *file, hid_t dxpl_id, H5D_t *dset, hid_t dapl_id)
     /* (If using the latest 'no modification time message' version support, the modification time is part of the object
      *  header and doesn't use a separate message -QAK)
      */
-    if(!(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_NO_MOD_TIME_MSG)))
+    if(H5F_LOW_BOUND(file) < H5F_LIBVER_V18)
         if(H5O_touch_oh(file, dxpl_id, oh, TRUE) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update modification time message")
 
@@ -1215,27 +1207,20 @@ H5D__create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
             HGOTO_ERROR(H5E_DATASET, H5E_BADVALUE, NULL, "compact dataset must have early space allocation")
     } /* end if */
 
-    /* Set the latest version of the layout, pline & fill messages, if requested */
-    if(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_DSET_MSG_FLAGS)) {
-        /* Set the latest version for the I/O pipeline message */
-	if(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_PLINE_MSG))
-	    if(H5O_pline_set_latest_version(&new_dset->shared->dcpl_cache.pline) < 0)
-		HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of I/O filter pipeline")
-
-        /* Set the latest version for the fill message */
-	if(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_FILL_MSG))
-	    /* Set the latest version for the fill value message */
-	    if(H5O_fill_set_latest_version(&new_dset->shared->dcpl_cache.fill) < 0)
-		HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of fill value")
-
-        /* Set the latest version for the layout message */
-	if(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_LAYOUT_MSG))
-	    /* Set the latest version for the layout message */
-	    if(H5D__layout_set_latest_version(&new_dset->shared->layout, new_dset->shared->space, &new_dset->shared->dcpl_cache) < 0)
-		HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of layout")
-    } /* end if */
-    else if(new_dset->shared->layout.version >= H5O_LAYOUT_VERSION_4) {
-	/* Use latest indexing type for layout message version >= 4 */
+    /* Set the version for the I/O pipeline message */
+    if(H5O_pline_set_version(file, &new_dset->shared->dcpl_cache.pline) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of I/O filter pipeline")
+
+    /* Set the version for the fill message */
+    if(H5O_fill_set_version(file, &new_dset->shared->dcpl_cache.fill) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of fill value")
+
+    /* Set the latest version for the layout message */
+    if(H5D__layout_set_version(file, &new_dset->shared->layout) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest version of layout")
+
+    if(new_dset->shared->layout.version >= H5O_LAYOUT_VERSION_4) {
+        /* Use latest indexing type for layout message version >= 4 */
         if(H5D__layout_set_latest_indexing(&new_dset->shared->layout, new_dset->shared->space, &new_dset->shared->dcpl_cache) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set latest indexing")
     } /* end if */
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
index ec18e86..08d7929 100644
--- a/src/H5Dlayout.c
+++ b/src/H5Dlayout.c
@@ -56,6 +56,13 @@
 /* Local Variables */
 /*******************/
 
+/* Format version bounds for layout */
+static const unsigned H5O_layout_ver_bounds[] = {
+    H5O_LAYOUT_VERSION_1,   /* H5F_LIBVER_EARLIEST */
+    H5O_LAYOUT_VERSION_3,   /* H5F_LIBVER_V18 */
+    H5O_LAYOUT_VERSION_LATEST   /* H5F_LIBVER_LATEST */
+};
+
 
 
 /*-------------------------------------------------------------------------
@@ -277,11 +284,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5D__layout_set_latest_version
+ * Function:    H5D__layout_set_version
  *
- * Purpose:     Set the encoding for a layout to the latest version.
- *              Part of the coding in this routine is moved to
- *              H5D__layout_set_latest_indexing().
+ * Purpose:     Set the version to encode a layout with.
  *
  * Return:      Non-negative on success/Negative on failure
  *
@@ -291,35 +296,33 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5D__layout_set_latest_version(H5O_layout_t *layout, const H5S_t *space, 
-    const H5D_dcpl_cache_t *dcpl_cache)
+H5D__layout_set_version(H5F_t *f, H5O_layout_t *layout)
 {
+    unsigned vers;
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_PACKAGE
+    FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
     HDassert(layout);
-    HDassert(space);
-    HDassert(dcpl_cache);
+    HDassert(f);
 
-    /* Set encoding of layout to latest version */
-    layout->version = H5O_LAYOUT_VERSION_LATEST;
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    layout->version = MAX(layout->version, H5O_layout_ver_bounds[H5F_LOW_BOUND(f)]);
 
-    /* Set the latest indexing type for the layout message */
-    if(H5D__layout_set_latest_indexing(layout, space, dcpl_cache) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest indexing type")
+    /* File bound check */
+    if(layout->version > H5O_layout_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_DATASET, H5E_BADRANGE, FAIL, "layout version out of bounds")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5D__layout_set_latest_version() */
+} /* end H5D__layout_set_version() */
 
 
 /*-------------------------------------------------------------------------
  * Function:    H5D__layout_set_latest_indexing
  *
  * Purpose:     Set the latest indexing type for a layout message
- *              This is moved from H5D_layout_set_latest_version().
  *
  * Return:      Non-negative on success/Negative on failure
  *
diff --git a/src/H5F.c b/src/H5F.c
index 211f1aa..1ee16e1 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -1633,7 +1633,6 @@ H5Fstart_swmr_write(hid_t file_id)
 
     if(file->shared->sblock->super_vers < HDF5_SUPERBLOCK_VERSION_3)
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "file superblock version should be at least 3")
-    HDassert((file->shared->latest_flags | H5F_LATEST_LAYOUT_MSG) > 0);
 
     /* Should not be marked for SWMR writing mode already */
     if(file->shared->sblock->status_flags & H5F_SUPER_SWMR_WRITE_ACCESS)
@@ -1899,9 +1898,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:   H5Fset_latest_format
+ * Function:   H5Fset_libver_bounds (Internal library use)
  *
- * Purpose:    Enable switching the "latest format" flag while a file is open.
+ * Purpose:    Set .... the "latest format" flag while a file is open.
  *
  * Return:     Non-negative on success/Negative on failure
  *
@@ -1910,33 +1909,28 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Fset_latest_format(hid_t file_id, hbool_t latest_format)
+H5Fset_libver_bounds(hid_t file_id, H5F_libver_t low, H5F_libver_t high)
 {
     H5F_t *f;                           /* File */
-    unsigned latest_flags;              /* Latest format flags for file */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "ib", file_id, latest_format);
+    H5TRACE3("e", "iFvFv", file_id, low, high);
 
     /* Check args */
     if(NULL == (f = (H5F_t *)H5I_object_verify(file_id, H5I_FILE)))
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "not a file ID")
 
-    /* Check if the value is changing */
-    latest_flags = H5F_USE_LATEST_FLAGS(f, H5F_LATEST_ALL_FLAGS);
-    if(latest_format != (H5F_LATEST_ALL_FLAGS == latest_flags)) {
-        /* Call the flush routine, for this file */
-        if(H5F__flush(f, H5AC_ind_read_dxpl_id, H5AC_rawdata_dxpl_id, FALSE) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "unable to flush file's cached information")
+    /* Call the flush routine, for this file */
+    if(H5F__flush(f, H5AC_ind_read_dxpl_id, H5AC_rawdata_dxpl_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "unable to flush file's cached information")
 
-        /* Toggle the 'latest format' flag */
-        H5F_SET_LATEST_FLAGS(f, latest_format ? H5F_LATEST_ALL_FLAGS : 0);
-    } /* end if */
+    f->shared->low_bound = low;
+    f->shared->high_bound = high;
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Fset_latest_format() */
+} /* end H5Fset_libver_bounds() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 4c5e00e..d145462 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -130,7 +130,6 @@ H5F_get_access_plist(H5F_t *f, hbool_t app_ref)
     H5FD_driver_prop_t driver_prop;         /* Property for driver ID & info */
     hbool_t driver_prop_copied = FALSE;     /* Whether the driver property has been set up */
     unsigned    efc_size = 0;
-    hbool_t	latest_format = FALSE;	    /* Always use the latest format? */
     hid_t	ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
@@ -167,10 +166,10 @@ H5F_get_access_plist(H5F_t *f, hbool_t app_ref)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't sieve buffer size")
     if(H5P_set(new_plist, H5F_ACS_SDATA_BLOCK_SIZE_NAME, &(f->shared->sdata_aggr.alloc_size)) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'small data' cache size")
-    if(f->shared->latest_flags > 0)
-        latest_format = TRUE;
-    if(H5P_set(new_plist, H5F_ACS_LATEST_FORMAT_NAME, &latest_format) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'latest format' flag")
+    if(H5P_set(new_plist, H5F_ACS_FORMAT_LOW_BOUND_NAME, &f->shared->low_bound) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'low' bound for library format versions")
+    if(H5P_set(new_plist, H5F_ACS_FORMAT_HIGH_BOUND_NAME, &f->shared->high_bound) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'high' bound for library format versions")
     if(H5P_set(new_plist, H5F_ACS_METADATA_READ_ATTEMPTS_NAME, &(f->shared->read_attempts)) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'read attempts ' flag")
     if(H5P_set(new_plist, H5F_ACS_OBJECT_FLUSH_CB_NAME, &(f->shared->object_flush)) < 0)
@@ -593,7 +592,6 @@ H5F_new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t
     else {
         H5P_genplist_t *plist;          /* Property list */
         unsigned        efc_size;       /* External file cache size */
-        hbool_t	latest_format;	        /* Always use the latest format?	*/
         size_t u;                       /* Local index variable */
 
         HDassert(lf != NULL);
@@ -675,13 +673,10 @@ H5F_new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get garbage collect reference")
         if(H5P_get(plist, H5F_ACS_SIEVE_BUF_SIZE_NAME, &(f->shared->sieve_buf_size)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get sieve buffer size")
-        if(H5P_get(plist, H5F_ACS_LATEST_FORMAT_NAME, &latest_format) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get 'latest format' flag")
-        /* For latest format or SWMR_WRITE, activate all latest version support */
-        if(latest_format)
-            f->shared->latest_flags |= H5F_LATEST_ALL_FLAGS;
-        else if(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE)
-            f->shared->latest_flags |= H5F_LATEST_LAYOUT_MSG;
+        if(H5P_get(plist, H5F_ACS_FORMAT_LOW_BOUND_NAME, &(f->shared->low_bound)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get 'low' bound for library format versions")
+        if(H5P_get(plist, H5F_ACS_FORMAT_HIGH_BOUND_NAME, &(f->shared->high_bound)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get 'high' bound for library format versions")
         if(H5P_get(plist, H5F_ACS_USE_MDC_LOGGING_NAME, &(f->shared->use_mdc_logging)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get 'use mdc logging' flag")
         if(H5P_get(plist, H5F_ACS_START_MDC_LOG_ON_ACCESS_NAME, &(f->shared->start_mdc_log_on_access)) < 0)
@@ -2787,34 +2782,3 @@ H5F_set_coll_md_read(H5F_t *f, H5P_coll_md_read_flag_t cmr)
     FUNC_LEAVE_NOAPI_VOID
 } /* H5F_set_coll_md_read() */
 #endif /* H5_HAVE_PARALLEL */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5F_set_latest_flags
- *
- * Purpose:     Set the latest_flags field with a new value.
- *
- * Return:      Success:        SUCCEED
- *              Failure:        FAIL
- *
- * Programmer:  Quincey Koziol
- *              4/26/16
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5F_set_latest_flags(H5F_t *f, unsigned flags)
-{
-    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(f->shared);
-    HDassert(0 == ((~flags) & H5F_LATEST_ALL_FLAGS));
-
-    f->shared->latest_flags = flags;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5F_set_latest_flags() */
-
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index d702506..cd6a295 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -300,7 +300,8 @@ struct H5F_file_t {
     hsize_t	threshold;	/* Threshold for alignment		*/
     hsize_t	alignment;	/* Alignment				*/
     unsigned	gc_ref;		/* Garbage-collect references?		*/
-    unsigned	latest_flags;	/* The latest version support */
+    H5F_libver_t    low_bound;  /* The 'low' bound of library format versions */
+    H5F_libver_t    high_bound; /* The 'high' bound of library format versions */
     hbool_t	store_msg_crt_idx;  /* Store creation index for object header messages?	*/
     unsigned	ncwfs;		/* Num entries on cwfs list		*/
     struct H5HG_heap_t **cwfs;	/* Global heap cache			*/
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index eba48de..3f03a96 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -272,6 +272,8 @@
 
 /* If the module using this macro is allowed access to the private variables, access them directly */
 #ifdef H5F_MODULE
+#define H5F_LOW_BOUND(F)        ((F)->shared->low_bound)
+#define H5F_HIGH_BOUND(F)       ((F)->shared->high_bound)
 #define H5F_INTENT(F)           ((F)->shared->flags)
 #define H5F_OPEN_NAME(F)        ((F)->open_name)
 #define H5F_ACTUAL_NAME(F)      ((F)->actual_name)
@@ -329,6 +331,8 @@
 #define H5F_FIRST_ALLOC_DEALLOC(F) ((F)->shared->first_alloc_dealloc)
 #define H5F_EOA_PRE_FSM_FSALLOC(F) ((F)->shared->eoa_pre_fsm_fsalloc)
 #else /* H5F_MODULE */
+#define H5F_LOW_BOUND(F)        (H5F_get_low_bound(F))
+#define H5F_HIGH_BOUND(F)       (H5F_get_high_bound(F))
 #define H5F_INTENT(F)           (H5F_get_intent(F))
 #define H5F_OPEN_NAME(F)        (H5F_get_open_name(F))
 #define H5F_ACTUAL_NAME(F)      (H5F_get_actual_name(F))
@@ -372,7 +376,6 @@
 #define H5F_SET_GRP_BTREE_SHARED(F, RC) (H5F_set_grp_btree_shared((F), (RC)))
 #define H5F_USE_TMP_SPACE(F)    (H5F_use_tmp_space(F))
 #define H5F_IS_TMP_ADDR(F, ADDR) (H5F_is_tmp_addr((F), (ADDR)))
-#define H5F_SET_LATEST_FLAGS(F, FL)  (H5F_set_latest_flags((F), (FL)))
 #ifdef H5_HAVE_PARALLEL
 #define H5F_COLL_MD_READ(F)     (H5F_coll_md_read(F))
 #endif /* H5_HAVE_PARALLEL */
@@ -481,7 +484,8 @@
 #define H5F_ACS_FAMILY_NEWSIZE_NAME             "family_newsize" /* New member size of family driver.  (private property only used by h5repart) */
 #define H5F_ACS_FAMILY_TO_SEC2_NAME             "family_to_sec2" /* Whether to convert family to sec2 driver.  (private property only used by h5repart) */
 #define H5F_ACS_MULTI_TYPE_NAME                 "multi_type"    /* Data type in multi file driver */
-#define H5F_ACS_LATEST_FORMAT_NAME              "latest_format" /* 'Use latest format version' flag */
+#define H5F_ACS_FORMAT_LOW_BOUND_NAME           "low_bound"     /* 'low' bound of library format versions */
+#define H5F_ACS_FORMAT_HIGH_BOUND_NAME          "high_bound"    /* 'high' bound of library format versions */
 #define H5F_ACS_WANT_POSIX_FD_NAME              "want_posix_fd" /* Internal: query the file descriptor from the core VFD, instead of the memory address */
 #define H5F_ACS_METADATA_READ_ATTEMPTS_NAME     "metadata_read_attempts" /* # of metadata read attempts */
 #define H5F_ACS_OBJECT_FLUSH_CB_NAME     	"object_flush_cb" 	 /* Object flush callback */
@@ -626,23 +630,6 @@
 #define H5SM_TABLE_MAGIC                "SMTB"          /* Shared Message Table */
 #define H5SM_LIST_MAGIC                 "SMLI"          /* Shared Message List */
 
-
-/* Latest format will activate the following latest version support */
-/* "latest_flags" in H5F_file_t */
-#define H5F_LATEST_DATATYPE             0x0001
-#define H5F_LATEST_DATASPACE            0x0002
-#define H5F_LATEST_ATTRIBUTE            0x0004
-#define H5F_LATEST_FILL_MSG             0x0008
-#define H5F_LATEST_PLINE_MSG            0x0010
-#define H5F_LATEST_LAYOUT_MSG           0x0020
-#define H5F_LATEST_NO_MOD_TIME_MSG      0x0040
-#define H5F_LATEST_STYLE_GROUP          0x0080
-#define H5F_LATEST_OBJ_HEADER           0x0100
-#define H5F_LATEST_SUPERBLOCK           0x0200
-#define H5F_LATEST_ALL_FLAGS            (H5F_LATEST_DATATYPE | H5F_LATEST_DATASPACE | H5F_LATEST_ATTRIBUTE | H5F_LATEST_FILL_MSG | H5F_LATEST_PLINE_MSG | H5F_LATEST_LAYOUT_MSG | H5F_LATEST_NO_MOD_TIME_MSG | H5F_LATEST_STYLE_GROUP | H5F_LATEST_OBJ_HEADER | H5F_LATEST_SUPERBLOCK)
-
-#define H5F_LATEST_DSET_MSG_FLAGS    (H5F_LATEST_FILL_MSG | H5F_LATEST_PLINE_MSG | H5F_LATEST_LAYOUT_MSG)
-
 /****************************/
 /* Library Private Typedefs */
 /****************************/
@@ -734,6 +721,8 @@ H5_DLL H5F_t *H5F_open(const char *name, unsigned flags, hid_t fcpl_id,
 H5_DLL herr_t H5F_try_close(H5F_t *f, hbool_t *was_closed/*out*/);
 
 /* Functions than retrieve values from the file struct */
+H5_DLL unsigned H5F_get_low_bound(const H5F_t *f);
+H5_DLL unsigned H5F_get_high_bound(const H5F_t *f);
 H5_DLL unsigned H5F_get_intent(const H5F_t *f);
 H5_DLL char *H5F_get_open_name(const H5F_t *f);
 H5_DLL char *H5F_get_actual_name(const H5F_t *f);
@@ -784,7 +773,6 @@ H5_DLL struct H5UC_t *H5F_grp_btree_shared(const H5F_t *f);
 H5_DLL herr_t H5F_set_grp_btree_shared(H5F_t *f, struct H5UC_t *rc);
 H5_DLL hbool_t H5F_use_tmp_space(const H5F_t *f);
 H5_DLL hbool_t H5F_is_tmp_addr(const H5F_t *f, haddr_t addr);
-H5_DLL herr_t H5F_set_latest_flags(H5F_t *f, unsigned flags);
 H5_DLL hsize_t H5F_get_alignment(const H5F_t *f);
 H5_DLL hsize_t H5F_get_threshold(const H5F_t *f);
 #ifdef H5_HAVE_PARALLEL
diff --git a/src/H5Fpublic.h b/src/H5Fpublic.h
index 1594cb2..9364ee2 100644
--- a/src/H5Fpublic.h
+++ b/src/H5Fpublic.h
@@ -175,10 +175,15 @@ typedef struct H5F_sect_info_t {
 
 /* Library's file format versions */
 typedef enum H5F_libver_t {
-    H5F_LIBVER_EARLIEST,        /* Use the earliest possible format for storing objects */
-    H5F_LIBVER_LATEST           /* Use the latest possible format available for storing objects*/
+    H5F_LIBVER_ERROR = -1,
+    H5F_LIBVER_EARLIEST = 0,    /* Use the earliest possible format for storing objects */
+    H5F_LIBVER_V18 = 1,         /* Use the latest v18 format for storing objects */
+    H5F_LIBVER_V110 = 2,        /* Use the latest v10 format for storing objects */
+    H5F_LIBVER_NBOUNDS
 } H5F_libver_t;
 
+#define H5F_LIBVER_LATEST   H5F_LIBVER_V110
+
 /* File space handling strategy */
 typedef enum H5F_fspace_strategy_t {
     H5F_FSPACE_STRATEGY_FSM_AGGR = 0,   /* Mechanisms: free-space managers, aggregators, and virtual file drivers */
@@ -255,7 +260,7 @@ H5_DLL herr_t H5Fstart_swmr_write(hid_t file_id);
 H5_DLL ssize_t H5Fget_free_sections(hid_t file_id, H5F_mem_t type,
     size_t nsects, H5F_sect_info_t *sect_info/*out*/);
 H5_DLL herr_t H5Fclear_elink_file_cache(hid_t file_id);
-H5_DLL herr_t H5Fset_latest_format(hid_t file_id, hbool_t latest_format);
+H5_DLL herr_t H5Fset_libver_bounds(hid_t file_id, H5F_libver_t low, H5F_libver_t high);
 H5_DLL herr_t H5Fstart_mdc_logging(hid_t file_id);
 H5_DLL herr_t H5Fstop_mdc_logging(hid_t file_id);
 H5_DLL herr_t H5Fget_mdc_logging_status(hid_t file_id,
diff --git a/src/H5Fquery.c b/src/H5Fquery.c
index 41cf4d2..4ba19b0 100644
--- a/src/H5Fquery.c
+++ b/src/H5Fquery.c
@@ -101,6 +101,56 @@ H5F_get_intent(const H5F_t *f)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5F_get_low_bound
+ *
+ * Purpose:	Quick and dirty routine to retrieve the file's low_bound.
+ *          (Mainly added to stop non-file routines from poking about in the
+ *          H5F_t data structure)
+ *
+ * Return:	low_bound on success/abort on failure (shouldn't fail)
+ *
+ * Programmer:	Vailin Choi; June 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_get_low_bound(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+
+    FUNC_LEAVE_NOAPI(f->shared->low_bound)
+} /* end H5F_get_low_bound() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_high_bound
+ *
+ * Purpose:	Quick and dirty routine to retrieve the file's high_bound.
+ *          (Mainly added to stop non-file routines from poking about in the
+ *          H5F_t data structure)
+ *
+ * Return:	high_bound on success/abort on failure (shouldn't fail)
+ *
+ * Programmer:	Vailin Choi; June 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_get_high_bound(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+
+    FUNC_LEAVE_NOAPI(f->shared->high_bound)
+} /* end H5F_get_high_bound() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5F_get_open_name
  *
  * Purpose:	Retrieve the name used to open a file.
@@ -800,34 +850,6 @@ H5F_gc_ref(const H5F_t *f)
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5F_use_latest_flags
- *
- * Purpose:	Retrieve the 'latest version support' for the file.
- *
- * Return:	Success:	Non-negative, the requested 'version support'
- *
- * 		Failure:	(can't happen)
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Mar  5 2007
- *
- *-------------------------------------------------------------------------
- */
-unsigned
-H5F_use_latest_flags(const H5F_t *f, unsigned fl)
-{
-    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    HDassert(f);
-    HDassert(f->shared);
-
-    FUNC_LEAVE_NOAPI(f->shared->latest_flags & (fl))
-} /* end H5F_use_latest_flags() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5F_get_fc_degree
  *
  * Purpose:	Retrieve the 'file close degree' for the file.
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 942a7ed..4490f48 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -59,7 +59,6 @@ static herr_t H5F__update_super_ext_driver_msg(H5F_t *f, hid_t dxpl_id);
 /* Package Variables */
 /*********************/
 
-
 /*****************************/
 /* Library Private Variables */
 /*****************************/
@@ -72,6 +71,12 @@ H5FL_DEFINE(H5F_super_t);
 /* Local Variables */
 /*******************/
 
+/* Format version bounds for superblock */
+static const unsigned HDF5_superblock_ver_bounds[] = {
+    HDF5_SUPERBLOCK_VERSION_DEF,    /* H5F_LIBVER_EARLIEST */
+    HDF5_SUPERBLOCK_VERSION_2,      /* H5F_LIBVER_V18 */
+    HDF5_SUPERBLOCK_VERSION_LATEST  /* H5F_LIBVER_LATEST */
+};
 
 
 /*-------------------------------------------------------------------------
@@ -405,13 +410,23 @@ H5F__super_read(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t initial
     if(NULL == (sblock = (H5F_super_t *)H5AC_protect(f, meta_dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, &udata, rw_flags)))
         HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load superblock")
 
-    if(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE)
-       	if(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_3)
-	    HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "invalid superblock version for SWMR_WRITE")
+     /* Upgrade low bound to at least V18 when encountering version 2 superblock */
+    if(sblock->super_vers == HDF5_SUPERBLOCK_VERSION_2)
+        f->shared->low_bound = MAX(H5F_LIBVER_V18, f->shared->low_bound);
+
+    /* Upgrade low bound to at least V110 when encountering version 3 superblock or SWMR_WRITE */
+    if((sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_3) || (H5F_INTENT(f) & H5F_ACC_SWMR_WRITE))
+        f->shared->low_bound = MAX(H5F_LIBVER_V110, f->shared->low_bound);
+
+    /* File bound check */
+    if(sblock->super_vers > HDF5_superblock_ver_bounds[f->shared->high_bound])
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version out of bounds (high bound)")
 
-    /* Enable all latest version support when file has v3 superblock */
-    if(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_3)
-	f->shared->latest_flags |= H5F_LATEST_ALL_FLAGS;
+    /* SWMR requires at least superblock version 3 */
+    if(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE) {
+        if(sblock->super_vers  < HDF5_superblock_ver_bounds[f->shared->low_bound])
+            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version out of bounds (low bound)")
+    }
 
     /* Pin the superblock in the cache */
     if(H5AC_pin_protected_entry(sblock) < 0)
@@ -971,14 +986,12 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
 	    f->shared->fs_page_size == H5F_FILE_SPACE_PAGE_SIZE_DEF))
         non_default_fs_settings = TRUE;
 
-    /* Bump superblock version if latest superblock version support is enabled */
-    if(H5F_USE_LATEST_FLAGS(f, H5F_LATEST_SUPERBLOCK))
-        super_vers = HDF5_SUPERBLOCK_VERSION_LATEST;
-    /* Bump superblock version to use version 3 superblock for SWMR writing */
-    else if((H5F_INTENT(f) & H5F_ACC_SWMR_WRITE))
+    if(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE) {
         super_vers = HDF5_SUPERBLOCK_VERSION_3;
+        f->shared->low_bound = MAX(H5F_LIBVER_V110, f->shared->low_bound);
+
     /* Bump superblock version to create superblock extension for SOHM info */
-    else if(f->shared->sohm_nindexes > 0)
+    } else if(f->shared->sohm_nindexes > 0)
         super_vers = HDF5_SUPERBLOCK_VERSION_2;
     /* 
      *	Bump superblock version to create superblock extension for:
@@ -996,6 +1009,13 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     else if(sblock->btree_k[H5B_CHUNK_ID] != HDF5_BTREE_CHUNK_IK_DEF)
         super_vers = HDF5_SUPERBLOCK_VERSION_1;
 
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    super_vers = MAX(super_vers, HDF5_superblock_ver_bounds[f->shared->low_bound]);
+
+    /* File bound check */
+    if(super_vers > HDF5_superblock_ver_bounds[f->shared->high_bound])
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "superblock version out of bounds")
+
     /* If a newer superblock version is required, set it here */
     if(super_vers != HDF5_SUPERBLOCK_VERSION_DEF) {
         H5P_genplist_t *c_plist;              /* Property list */
diff --git a/src/H5Gobj.c b/src/H5Gobj.c
index d2dc83b..832c9a7 100644
--- a/src/H5Gobj.c
+++ b/src/H5Gobj.c
@@ -185,7 +185,7 @@ H5G__obj_create_real(H5F_t *f, hid_t dxpl_id, const H5O_ginfo_t *ginfo,
     H5G_obj_create_t *gcrt_info, H5O_loc_t *oloc/*out*/)
 {
     size_t hdr_size;                    /* Size of object header to request */
-    hbool_t use_latest_format;          /* Flag indicating the new group format should be used */
+    hbool_t use_v18_latest_format;      /* Flag indicating the new group format should be used */
     hid_t gcpl_id = gcrt_info->gcpl_id; /* Group creation property list ID */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -202,24 +202,23 @@ H5G__obj_create_real(H5F_t *f, hid_t dxpl_id, const H5O_ginfo_t *ginfo,
 
     /* Check for invalid access request */
     if(0 == (H5F_INTENT(f) & H5F_ACC_RDWR))
-	HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "no write intent on file")
+        HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "no write intent on file")
 
     /* Check for using the latest version of the group format */
     /* (add more checks for creating "new format" groups when needed) */
-    if(H5F_USE_LATEST_FLAGS(f, H5F_LATEST_STYLE_GROUP) || linfo->track_corder
-            || (pline && pline->nused))
-        use_latest_format = TRUE;
+    if((H5F_LOW_BOUND(f) >= H5F_LIBVER_V18) || linfo->track_corder || (pline && pline->nused))
+        use_v18_latest_format = TRUE;
     else
-        use_latest_format = FALSE;
+        use_v18_latest_format = FALSE;
 
     /* Make certain that the creation order is being tracked if an index is
      *  going to be built on it.
      */
     if(linfo->index_corder && !linfo->track_corder)
-	HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "must track creation order to create index for it")
+        HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "must track creation order to create index for it")
 
     /* Check if we should be using the latest version of the group format */
-    if(use_latest_format) {
+    if(use_v18_latest_format) {
         H5O_link_t lnk;                     /* Temporary link message info for computing message size */
         char null_char = '\0';              /* Character for creating null string */
         size_t ginfo_size;                  /* Size of the group info message */
@@ -262,10 +261,10 @@ H5G__obj_create_real(H5F_t *f, hid_t dxpl_id, const H5O_ginfo_t *ginfo,
      * incremented if the object is added to the group directed graph.
      */
     if(H5O_create(f, dxpl_id, hdr_size, (size_t)1, gcpl_id, oloc/*out*/) < 0)
-	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create header")
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create header")
 
     /* Check for format of group to create */
-    if(use_latest_format) {
+    if(use_v18_latest_format) {
         /* Insert link info message */
         /* (Casting away const OK - QAK) */
         if(H5O_msg_create(oloc, H5O_LINFO_ID, 0, H5O_UPDATE_TIME, (void *)linfo, dxpl_id) < 0)
diff --git a/src/H5HFhdr.c b/src/H5HFhdr.c
index 2f01ce6..89b3b47 100644
--- a/src/H5HFhdr.c
+++ b/src/H5HFhdr.c
@@ -424,11 +424,9 @@ H5HF_hdr_create(H5F_t *f, hid_t dxpl_id, const H5HF_create_t *cparam)
         if(NULL == H5O_msg_copy(H5O_PLINE_ID, &(cparam->pline), &(hdr->pline)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTCOPY, HADDR_UNDEF, "can't copy I/O filter pipeline")
 
-        /* Pay attention to the latest version flag for the file */
-        if(H5F_USE_LATEST_FLAGS(hdr->f, H5F_LATEST_PLINE_MSG))
-            /* Set the latest version for the I/O pipeline message */
-            if(H5O_pline_set_latest_version(&(hdr->pline)) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTSET, HADDR_UNDEF, "can't set latest version of I/O filter pipeline")
+        /* Set the version for the I/O pipeline message */
+        if(H5O_pline_set_version(hdr->f, &(hdr->pline)) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTSET, HADDR_UNDEF, "can't set version of I/O filter pipeline")
 
         /* Compute the I/O filters' encoded size */
         if(0 == (hdr->filter_len = (unsigned)H5O_msg_raw_size(hdr->f, H5O_PLINE_ID, FALSE, &(hdr->pline))))
diff --git a/src/H5O.c b/src/H5O.c
index 152e6cc..ab5d07b 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -137,6 +137,7 @@ const H5O_msg_class_t *const H5O_msg_class_g[] = {
 #endif /* H5O_ENABLE_BOGUS */
 };
 
+
 /* Declare a free list to manage the H5O_t struct */
 H5FL_DEFINE(H5O_t);
 
@@ -180,6 +181,12 @@ static const H5O_obj_class_t *const H5O_obj_class_g[] = {
     H5O_OBJ_GROUP,		/* Group object (H5O_TYPE_GROUP - 0) */
 };
 
+/* Format version bounds for object header */
+static const unsigned H5O_obj_ver_bounds[] = {
+    H5O_VERSION_1,      /* H5F_LIBVER_EARLIEST */
+    H5O_VERSION_2,      /* H5F_LIBVER_V18 */
+    H5O_VERSION_LATEST  /* H5F_LIBVER_LATEST */
+};
 
 
 /*-------------------------------------------------------------------------
@@ -1214,6 +1221,51 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5O_set_version
+ *
+ * Purpose:     Sets the correct version to encode the object header.
+ *              Chooses the oldest version possible, unless the file's
+ *              low bound indicates otherwise.
+ *
+ * Return:	Success:    Non-negative
+ *		    Failure:	Negative
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              Jul 17 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_set_version(H5F_t *f, H5O_t *oh, uint8_t oh_flags, hbool_t store_msg_crt_idx)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* check arguments */
+    HDassert(f);
+    HDassert(oh);
+
+    /* Set the correct version to encode object header with */
+    if(store_msg_crt_idx || (oh_flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED))
+        oh->version = H5O_VERSION_2;
+    else
+        oh->version = H5O_VERSION_1;
+
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    oh->version = MAX(oh->version, (uint8_t)H5O_obj_ver_bounds[H5F_LOW_BOUND(f)]);
+
+    /* File bound check */
+    if(oh->version > H5O_obj_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_OHDR, H5E_BADRANGE, FAIL, "object header version out of bounds")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_set_version() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5O_create
  *
  * Purpose:	Creates a new object header. Allocates space for it and
@@ -1222,10 +1274,10 @@ done:
  *              closed by calling H5O_close().
  *
  * Return:	Success:	Non-negative, the ENT argument contains
- *				information about the object header,
- *				including its address.
+ *	                    information about the object header,
+ *                      including its address.
  *
- *		Failure:	Negative
+ *          Failure:	Negative
  *
  * Programmer:	Robb Matzke
  *		matzke@llnl.gov
@@ -1237,14 +1289,14 @@ herr_t
 H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, size_t initial_rc,
     hid_t ocpl_id, H5O_loc_t *loc/*out*/)
 {
-    H5P_genplist_t  *oc_plist;          /* Object creation property list */
-    H5O_t      *oh = NULL;              /* Object header created */
-    haddr_t     oh_addr;                /* Address of initial object header */
-    size_t      oh_size;                /* Size of initial object header */
-    uint8_t	oh_flags;		/* Object header's initial status flags */
-    unsigned    insert_flags = H5AC__NO_FLAGS_SET; /* Flags for inserting object header into cache */
-    hbool_t     store_msg_crt_idx;      /* Whether to always store message creation indices for this file */
-    herr_t      ret_value = SUCCEED;    /* return value */
+    H5P_genplist_t *oc_plist;   /* Object creation property list */
+    H5O_t *oh = NULL;           /* Object header created */
+    haddr_t oh_addr;            /* Address of initial object header */
+    size_t oh_size;             /* Size of initial object header */
+    hbool_t store_msg_crt_idx;  /* Whether to always store message creation indices for this file */
+    uint8_t	oh_flags;	        /* Object header's initial status flags */
+    unsigned insert_flags = H5AC__NO_FLAGS_SET; /* Flags for inserting object header into cache */
+    herr_t ret_value = SUCCEED;                 /* return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
@@ -1274,10 +1326,10 @@ H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, size_t initial_rc,
 
     /* Initialize file-specific information for object header */
     store_msg_crt_idx = H5F_STORE_MSG_CRT_IDX(f);
-    if(H5F_USE_LATEST_FLAGS(f, H5F_LATEST_OBJ_HEADER) || store_msg_crt_idx || (oh_flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED))
-        oh->version = H5O_VERSION_LATEST;
-    else
-        oh->version = H5O_VERSION_1;
+
+    if(H5O_set_version(f, oh, oh_flags, store_msg_crt_idx) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set version of objecdt header")
+
     oh->sizeof_size = H5F_SIZEOF_SIZE(f);
     oh->sizeof_addr = H5F_SIZEOF_ADDR(f);
     oh->swmr_write = !!(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE);
diff --git a/src/H5Ofill.c b/src/H5Ofill.c
index 5419762..613b521 100644
--- a/src/H5Ofill.c
+++ b/src/H5Ofill.c
@@ -151,6 +151,13 @@ const H5O_msg_class_t H5O_MSG_FILL_NEW[1] = {{
     H5O_fill_new_shared_debug	/*debug the message			*/
 }};
 
+/* Format version bounds for fill value */
+static const unsigned H5O_fill_ver_bounds[] = {
+    H5O_FILL_VERSION_1,         /* H5F_LIBVER_EARLIEST */
+    H5O_FILL_VERSION_3,     /* H5F_LIBVER_V18 */
+    H5O_FILL_VERSION_LATEST /* H5F_LIBVER_LATEST */
+};
+
 /* Masks, shift values & flags for fill value message */
 #define H5O_FILL_MASK_ALLOC_TIME        0x03
 #define H5O_FILL_SHIFT_ALLOC_TIME       0
@@ -997,11 +1004,11 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5O_fill_set_latest_version
+ * Function:    H5O_fill_set_version
  *
- * Purpose:     Set the encoding for a fill value to the latest version.
+ * Purpose:     Set the version to encode a fill value with.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
  *              Tuesday, July 24, 2007
@@ -1009,16 +1016,24 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5O_fill_set_latest_version(H5O_fill_t *fill)
+H5O_fill_set_version(H5F_t *f, H5O_fill_t *fill)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    herr_t ret_value = SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
+    HDassert(f);
     HDassert(fill);
 
-    /* Set encoding of fill value to latest version */
-    fill->version = H5O_FILL_VERSION_LATEST;
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    fill->version = MAX(fill->version, H5O_fill_ver_bounds[H5F_LOW_BOUND(f)]);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5O_fill_set_latest_version() */
+    /* File bound check */
+    if(fill->version > H5O_fill_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_OHDR, H5E_BADRANGE, FAIL, "Filter pipeline version out of bounds")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_fill_set_version() */
 
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index b0c67d1..77d2130 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -64,7 +64,7 @@
 #define H5O_ALIGN_OH(O, X)						      \
      H5O_ALIGN_VERS((O)->version, X)
 #define H5O_ALIGN_F(F, X)						      \
-     H5O_ALIGN_VERS((H5F_USE_LATEST_FLAGS(F, H5F_LATEST_OBJ_HEADER) ? H5O_VERSION_LATEST : H5O_VERSION_1), X)
+     H5O_ALIGN_VERS(((H5F_LOW_BOUND(F) >= H5F_LIBVER_V18) ? H5O_VERSION_LATEST : H5O_VERSION_1), X)
 
 /* Size of checksum (on disk) */
 #define H5O_SIZEOF_CHKSUM               4
@@ -136,7 +136,7 @@
 #define H5O_SIZEOF_MSGHDR_OH(O)						      \
     H5O_SIZEOF_MSGHDR_VERS((O)->version, (O)->flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED)
 #define H5O_SIZEOF_MSGHDR_F(F, C)						      \
-    H5O_SIZEOF_MSGHDR_VERS((H5F_USE_LATEST_FLAGS(F, H5F_LATEST_OBJ_HEADER) || H5F_STORE_MSG_CRT_IDX(F)) ? H5O_VERSION_LATEST : H5O_VERSION_1, (C))
+    H5O_SIZEOF_MSGHDR_VERS(((H5F_LOW_BOUND(F) >= H5F_LIBVER_V18) || H5F_STORE_MSG_CRT_IDX(F)) ? H5O_VERSION_LATEST : H5O_VERSION_1, (C))
 
 /*
  * Size of chunk "header" for each chunk
@@ -556,7 +556,6 @@ H5_DLLVAR const H5O_obj_class_t H5O_OBJ_DATASET[1];
 /* Datatype Object. (H5O_TYPE_NAMED_DATATYPE - 2) */
 H5_DLLVAR const H5O_obj_class_t H5O_OBJ_DATATYPE[1];
 
-
 /* Package-local function prototypes */
 H5_DLL herr_t H5O_msg_flush(H5F_t *f, H5O_t *oh, H5O_mesg_t *mesg);
 H5_DLL herr_t H5O_flush_msgs(H5F_t *f, H5O_t *oh);
diff --git a/src/H5Opline.c b/src/H5Opline.c
index 2e52dbb..c1ff183 100644
--- a/src/H5Opline.c
+++ b/src/H5Opline.c
@@ -89,6 +89,12 @@ const H5O_msg_class_t H5O_MSG_PLINE[1] = {{
     H5O_pline_shared_debug	/* debug the message		*/
 }};
 
+/* Format version bounds for filter pipleline */
+static const unsigned H5O_pline_ver_bounds[] = {
+    H5O_PLINE_VERSION_1,        /* H5F_LIBVER_EARLIEST */
+    H5O_PLINE_VERSION_2,        /* H5F_LIBVER_V18 */
+    H5O_PLINE_VERSION_LATEST    /* H5F_LIBVER_LATEST */
+};
 
 /* Declare a free list to manage the H5O_pline_t struct */
 H5FL_DEFINE(H5O_pline_t);
@@ -664,11 +670,11 @@ H5O_pline_debug(H5F_t H5_ATTR_UNUSED *f, hid_t H5_ATTR_UNUSED dxpl_id, const voi
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5O_pline_set_latest_version
+ * Function:    H5O_pline_set_version
  *
- * Purpose:     Set the encoding for a I/O filter pipeline to the latest version.
+ * Purpose:     Set the version to encode an I/O filter pipeline with.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
  *              Tuesday, July 24, 2007
@@ -676,16 +682,23 @@ H5O_pline_debug(H5F_t H5_ATTR_UNUSED *f, hid_t H5_ATTR_UNUSED dxpl_id, const voi
  *-------------------------------------------------------------------------
  */
 herr_t
-H5O_pline_set_latest_version(H5O_pline_t *pline)
+H5O_pline_set_version(H5F_t *f, H5O_pline_t *pline)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    herr_t ret_value = SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
+    HDassert(f);
     HDassert(pline);
 
-    /* Set encoding of I/O pipeline to latest version */
-    pline->version = H5O_PLINE_VERSION_LATEST;
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    pline->version = MAX(pline->version, H5O_pline_ver_bounds[H5F_LOW_BOUND(f)]);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5O_pline_set_latest_version() */
+    /* File bound check */
+    if(pline->version > H5O_pline_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_PLINE, H5E_BADRANGE, FAIL, "Filter pipeline version out of bounds")
 
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_pline_set_version() */
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 563f8fa..4d48205 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -961,14 +961,14 @@ H5_DLL hsize_t H5O_efl_total_size(H5O_efl_t *efl);
 /* Fill value operators */
 H5_DLL herr_t H5O_fill_reset_dyn(H5O_fill_t *fill);
 H5_DLL herr_t H5O_fill_convert(H5O_fill_t *fill, H5T_t *type, hbool_t *fill_changed, hid_t dxpl_id);
-H5_DLL herr_t H5O_fill_set_latest_version(H5O_fill_t *fill);
+H5_DLL herr_t H5O_fill_set_version(H5F_t * f, H5O_fill_t *fill);
 
 /* Link operators */
 H5_DLL herr_t H5O_link_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     void *_mesg);
 
 /* Filter pipeline operators */
-H5_DLL herr_t H5O_pline_set_latest_version(H5O_pline_t *pline);
+H5_DLL herr_t H5O_pline_set_version(H5F_t *f, H5O_pline_t *pline);
 
 /* Shared message operators */
 H5_DLL herr_t H5O_set_shared(H5O_shared_t *dst, const H5O_shared_t *src);
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 1b0a4b9..a1d53cc 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -142,11 +142,19 @@
 #define H5F_ACS_MULTI_TYPE_DEF                  H5FD_MEM_DEFAULT
 #define H5F_ACS_MULTI_TYPE_ENC                  H5P__facc_multi_type_enc
 #define H5F_ACS_MULTI_TYPE_DEC                  H5P__facc_multi_type_dec
-/* Definition for 'use latest format version' flag */
-#define H5F_ACS_LATEST_FORMAT_SIZE              sizeof(hbool_t)
-#define H5F_ACS_LATEST_FORMAT_DEF               FALSE
-#define H5F_ACS_LATEST_FORMAT_ENC               H5P__encode_hbool_t
-#define H5F_ACS_LATEST_FORMAT_DEC               H5P__decode_hbool_t
+
+/* Definition for "low" bound of library format versions */
+#define H5F_ACS_FORMAT_LOW_BOUND_SIZE       sizeof(H5F_libver_t)
+#define H5F_ACS_FORMAT_LOW_BOUND_DEF        H5F_LIBVER_EARLIEST
+#define H5F_ACS_FORMAT_LOW_BOUND_ENC        H5P__facc_libver_type_enc
+#define H5F_ACS_FORMAT_LOW_BOUND_DEC        H5P__facc_libver_type_dec
+
+/* Definition for "high" bound of library format versions */
+#define H5F_ACS_FORMAT_HIGH_BOUND_SIZE      sizeof(H5F_libver_t)
+#define H5F_ACS_FORMAT_HIGH_BOUND_DEF       H5F_LIBVER_LATEST
+#define H5F_ACS_FORMAT_HIGH_BOUND_ENC       H5P__facc_libver_type_enc
+#define H5F_ACS_FORMAT_HIGH_BOUND_DEC       H5P__facc_libver_type_dec
+
 /* Definition for whether to query the file descriptor from the core VFD
  * instead of the memory address.  (Private to library)
  */
@@ -290,6 +298,8 @@ static herr_t H5P__facc_fclose_degree_enc(const void *value, void **_pp, size_t
 static herr_t H5P__facc_fclose_degree_dec(const void **pp, void *value);
 static herr_t H5P__facc_multi_type_enc(const void *value, void **_pp, size_t *size);
 static herr_t H5P__facc_multi_type_dec(const void **_pp, void *value);
+static herr_t H5P__facc_libver_type_enc(const void *value, void **_pp, size_t *size);
+static herr_t H5P__facc_libver_type_dec(const void **_pp, void *value);
 
 /* Metadata cache log location property callbacks */
 static herr_t H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size);
@@ -354,7 +364,10 @@ static const hsize_t H5F_def_family_offset_g = H5F_ACS_FAMILY_OFFSET_DEF;
 static const hsize_t H5F_def_family_newsize_g = H5F_ACS_FAMILY_NEWSIZE_DEF;        /* Default size of new files for family VFD */
 static const hbool_t H5F_def_family_to_sec2_g = H5F_ACS_FAMILY_TO_SEC2_DEF;        /* Default ?? for family VFD */
 static const H5FD_mem_t H5F_def_mem_type_g = H5F_ACS_MULTI_TYPE_DEF;               /* Default file space type for multi VFD */
-static const hbool_t H5F_def_latest_format_g = H5F_ACS_LATEST_FORMAT_DEF;          /* Default setting for "use the latest version of the format" flag */
+
+static const H5F_libver_t H5F_def_format_low_bound_g = H5F_ACS_FORMAT_LOW_BOUND_DEF;    /* Default setting for "low" bound of format version */
+static const H5F_libver_t H5F_def_format_high_bound_g = H5F_ACS_FORMAT_HIGH_BOUND_DEF;  /* Default setting for "high" bound of format version */
+
 static const hbool_t H5F_def_want_posix_fd_g = H5F_ACS_WANT_POSIX_FD_DEF;          /* Default setting for retrieving 'handle' from core VFD */
 static const unsigned H5F_def_efc_size_g = H5F_ACS_EFC_SIZE_DEF;                   /* Default external file cache size */
 static const H5FD_file_image_info_t H5F_def_file_image_info_g = H5F_ACS_FILE_IMAGE_INFO_DEF;                 /* Default file image info and callbacks */
@@ -493,9 +506,15 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
-    /* Register the 'use the latest version of the format' flag */
-    if(H5P_register_real(pclass, H5F_ACS_LATEST_FORMAT_NAME, H5F_ACS_LATEST_FORMAT_SIZE, &H5F_def_latest_format_g, 
-            NULL, NULL, NULL, H5F_ACS_LATEST_FORMAT_ENC, H5F_ACS_LATEST_FORMAT_DEC, 
+    /* Register the 'low' bound of library format versions */
+    if(H5P_register_real(pclass, H5F_ACS_FORMAT_LOW_BOUND_NAME, H5F_ACS_FORMAT_LOW_BOUND_SIZE, &H5F_def_format_low_bound_g,
+            NULL, NULL, NULL, H5F_ACS_FORMAT_LOW_BOUND_ENC, H5F_ACS_FORMAT_LOW_BOUND_DEC,
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
+    /* Register the 'high' bound of library format versions */
+    if(H5P_register_real(pclass, H5F_ACS_FORMAT_HIGH_BOUND_NAME, H5F_ACS_FORMAT_HIGH_BOUND_SIZE, &H5F_def_format_high_bound_g,
+            NULL, NULL, NULL, H5F_ACS_FORMAT_HIGH_BOUND_ENC, H5F_ACS_FORMAT_HIGH_BOUND_DEC,
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
@@ -2303,6 +2322,24 @@ done:
  *      releases and then map down to the previous actual library release which
  *      had a format change.
  *
+ * Note #3: The enumerated define for H5F_libver_t in 1.10 is:
+ *      typedef enum H5F_libver_t {
+ *          H5F_LIBVER_ERROR = -1,
+ *          H5F_LIBVER_EARLIEST = 0,
+ *          H5F_LIBVER_V18 = 1,
+ *          H5F_LIBVER_V110 = 2,
+ *          H5F_LIBVER_NBOUNDS
+ *      } H5F_libver_t;
+ *      #define H5F_LIBVER_LATEST       H5F_LIBVER_V110
+ *
+ *      The library supports five pairs of (low, high) combinations via H5Pset_libver_bounds():
+ *      1) H5F_LIBVER_EARLIEST, H5F_LIBVER_V18
+ *      2) H5F_LIBVER_EARLIEST, H5F_LIBVER_LATEST
+ *      4) H5F_LIBVER_V18, H5F_LIBVER_V18
+ *      4) H5F_LIBVER_V18, H5F_LIBVER_LATEST
+ *      5) H5F_LIBVER_LATEST, H5F_LIBVER_LATEST
+ *      See detailed description in the RFC: Setting Bounds for Object Creation in HDF5 1.10.0.
+ *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
@@ -2311,32 +2348,38 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_libver_bounds(hid_t plist_id, H5F_libver_t low,
-    H5F_libver_t high)
+H5Pset_libver_bounds(hid_t plist_id, H5F_libver_t low, H5F_libver_t high)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
-    hbool_t latest;             /* Whether to use the latest version or not */
     herr_t ret_value = SUCCEED;   /* return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE3("e", "iFvFv", plist_id, low, high);
 
     /* Check args */
-    /* (Note that this is _really_ restricted right now, we'll want to loosen
-     *  this up more as we add features - QAK)
-     */
-    if(high != H5F_LIBVER_LATEST)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid high library version bound")
+    if(low < 0 || low > H5F_LIBVER_LATEST)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "low bound is not valid")
+
+    if(high < 0 || high > H5F_LIBVER_LATEST)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "high bound is not valid")
+
+    /* (earliest, earliest), (latest, earliest), (v18, earliest) are not valid combinations */
+    if(high == H5F_LIBVER_EARLIEST)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Invalid (low,high) combination of library version bound")
+
+    /* (latest, v18) is not valid combination */
+    if(high < low)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Invalid (low,high) combination of library version bound")
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
     /* Set values */
-    latest = (hbool_t)((low == H5F_LIBVER_LATEST) ? TRUE : FALSE);
-    if(H5P_set(plist, H5F_ACS_LATEST_FORMAT_NAME, &latest) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set library version bounds")
-
+    if(H5P_set(plist, H5F_ACS_FORMAT_LOW_BOUND_NAME, &low) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set low bound for library format versions")
+    if(H5P_set(plist, H5F_ACS_FORMAT_HIGH_BOUND_NAME, &high) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set high bound for library format versions")
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pset_libver_bounds() */
@@ -2346,7 +2389,7 @@ done:
  * Function:	H5Pget_libver_bounds
  *
  * Purpose:	Returns the current settings for the library version format bounds
- *      from a file access property list.
+ *          from a file access property list.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -2360,7 +2403,6 @@ H5Pget_libver_bounds(hid_t plist_id, H5F_libver_t *low/*out*/,
     H5F_libver_t *high/*out*/)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
-    hbool_t latest;             /* Whether to use the latest version or not */
     herr_t ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
@@ -2369,17 +2411,17 @@ H5Pget_libver_bounds(hid_t plist_id, H5F_libver_t *low/*out*/,
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    
+     /* Get values */
+    if(low) {
+        if(H5P_get(plist, H5F_ACS_FORMAT_LOW_BOUND_NAME, low) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get low bound for library format versions")
+    }
 
-    /* Get value */
-    if(H5P_get(plist, H5F_ACS_LATEST_FORMAT_NAME, &latest) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get library version bounds")
-
-    /* Check for setting values to return */
-    /* (Again, this is restricted now, we'll need to open it up later -QAK) */
-    if(low)
-        *low = latest ? H5F_LIBVER_LATEST : H5F_LIBVER_EARLIEST;
-    if(high)
-        *high = H5F_LIBVER_LATEST;
+    if(high) {
+        if(H5P_get(plist, H5F_ACS_FORMAT_HIGH_BOUND_NAME, high) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get high bound for library format versions")
+    }
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -3795,6 +3837,76 @@ H5P__facc_multi_type_dec(const void **_pp, void *_value)
 
 
 /*-------------------------------------------------------------------------
+ * Function:       H5P__facc_libver_type_enc
+ *
+ * Purpose:        Callback routine which is called whenever the 'low' or
+ *                 'high' bound of library format versions property in the
+ *                 file access property list is encoded.
+ *
+ * Return:	   Success:	Non-negative
+ *		   Failure:	Negative
+ *
+ * Programmer 
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_libver_type_enc(const void *value, void **_pp, size_t *size)
+{
+    const H5F_libver_t *type = (const H5F_libver_t *)value; /* Create local alias for values */
+    uint8_t **pp = (uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity check */
+    HDassert(type);
+    HDassert(size);
+
+    /* Encode */
+    if(NULL != *pp)
+        *(*pp)++ = (uint8_t)*type;
+
+    /* Size */
+    (*size)++;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__facc_libver_type_enc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P__facc_libver_type_dec
+ *
+ * Purpose:        Callback routine which is called whenever the 'low' or
+ *                 'high' bound of library format versions property in the
+ *                 file access property list is decoded.
+ *
+ * Return:	   Success:	Non-negative
+ *		   Failure:	Negative
+ *
+ * Programmer:     
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__facc_libver_type_dec(const void **_pp, void *_value)
+{
+    H5F_libver_t *type = (H5F_libver_t *)_value;
+    const uint8_t **pp = (const uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(pp);
+    HDassert(*pp);
+    HDassert(type);
+
+    /* Decode */
+    *type = (H5F_libver_t)*(*pp)++;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__facc_libver_type_dec() */
+
+/*-------------------------------------------------------------------------
  * Function:	H5Pset_core_write_tracking
  *
  * Purpose:	Enables/disables core VFD write tracking and page
diff --git a/src/H5S.c b/src/H5S.c
index 9ac40a7..01cacf0 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -84,6 +84,13 @@ static const H5I_class_t H5I_DATASPACE_CLS[1] = {{
     (H5I_free_t)H5S_close	/* Callback routine for closing objects of this class */
 }};
 
+/* Format version bounds for dataspace */
+static const unsigned H5O_sdspace_ver_bounds[] = {
+    H5O_SDSPACE_VERSION_1,      /* H5F_LIBVER_EARLIEST */
+    H5O_SDSPACE_VERSION_2,      /* H5F_LIBVER_V18 */
+    H5O_SDSPACE_VERSION_LATEST  /* H5F_LIBVER_LATEST */
+};
+
 /* Flag indicating "top" of interface has been initialized */
 static hbool_t H5S_top_package_initialize_s = FALSE;
 
@@ -2167,11 +2174,11 @@ H5S_extent_nelem(const H5S_extent_t *ext)
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5S_set_latest_version
+ * Function:    H5S_set_version
  *
- * Purpose:     Set the encoding for a dataspace to the latest version.
+ * Purpose:     Set the version to encode a dataspace with.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
  *              Tuesday, July 24, 2007
@@ -2179,18 +2186,27 @@ H5S_extent_nelem(const H5S_extent_t *ext)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5S_set_latest_version(H5S_t *ds)
+H5S_set_version(H5F_t *f, H5S_t *ds)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    herr_t ret_value = SUCCEED;   /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
+    HDassert(f);
     HDassert(ds);
 
-    /* Set encoding of extent to latest version */
-    ds->extent.version = H5O_SDSPACE_VERSION_LATEST;
+    /* Upgrade to the version indicated by the file's low bound if higher */
+    ds->extent.version = MAX(ds->extent.version, H5O_sdspace_ver_bounds[H5F_LOW_BOUND(f)]);
+
+    /* File bound check */
+    if(ds->extent.version > H5O_sdspace_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_DATASET, H5E_BADRANGE, FAIL, "Dataspace version out of bounds")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5S_set_latest_version() */
+} /* end H5S_set_version() */
 
 #ifndef H5_NO_DEPRECATED_SYMBOLS
 
diff --git a/src/H5Sprivate.h b/src/H5Sprivate.h
index 60e0630..7483690 100644
--- a/src/H5Sprivate.h
+++ b/src/H5Sprivate.h
@@ -217,7 +217,7 @@ H5_DLL herr_t H5S_set_extent_simple(H5S_t *space, unsigned rank,
 H5_DLL H5S_t *H5S_create(H5S_class_t type);
 H5_DLL H5S_t *H5S_create_simple(unsigned rank, const hsize_t dims[/*rank*/],
     const hsize_t maxdims[/*rank*/]);
-H5_DLL herr_t H5S_set_latest_version(H5S_t *ds);
+H5_DLL herr_t H5S_set_version(H5F_t *f, H5S_t *ds);
 H5_DLL herr_t H5S_encode(H5S_t *obj, unsigned char **p, size_t *nalloc);
 H5_DLL H5S_t *H5S_decode(const unsigned char **p);
 H5_DLL herr_t H5S_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg, FILE *stream,
diff --git a/src/H5T.c b/src/H5T.c
index a525cd5..23685b7 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -539,6 +539,13 @@ static const H5I_class_t H5I_DATATYPE_CLS[1] = {{
     (H5I_free_t)H5T_close    /* Callback routine for closing objects of this class */
 }};
 
+/* Format version bounds for datatype */
+static const unsigned H5O_dtype_ver_bounds[] = {
+    H5O_DTYPE_VERSION_1,        /* H5F_LIBVER_EARLIEST */
+    H5O_DTYPE_VERSION_3,    /* H5F_LIBVER_V18 */
+    H5O_DTYPE_VERSION_LATEST    /* H5F_LIBVER_LATEST */
+};
+
 /* Flag indicating "top" of interface has been initialized */
 static hbool_t H5T_top_package_initialize_s = FALSE;
 
@@ -5403,9 +5410,11 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5T_set_latest_version
+ * Function:    H5T_set_version
  *
- * Purpose:     Set the encoding for a datatype to the latest version.
+ * Purpose:     Set the encoding for a datatype to the version indicated by
+ *              the file's low bound if that is higher than the datatype's 
+ *              version.
  *
  * Return:      Non-negative on success/Negative on failure
  *
@@ -5415,22 +5424,31 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5T_set_latest_version(H5T_t *dt)
+H5T_set_version(H5F_t *f, H5T_t *dt)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    unsigned vers;                  /* The version */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Sanity check */
+    HDassert(f);
     HDassert(dt);
 
-    /* Upgrade the format version for the datatype to the latest */
-    if(H5T__upgrade_version(dt, H5O_DTYPE_VERSION_LATEST) < 0)
-        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "can't upgrade datatype encoding")
+    vers = H5O_dtype_ver_bounds[H5F_LOW_BOUND(f)];
+    if(vers > dt->shared->version) {
+        /* Upgrade the format version for the datatype */
+        if(H5T__upgrade_version(dt, vers) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "can't upgrade datatype encoding")
+    }
+    
+    /* File bound check */
+    if(dt->shared->version > H5O_dtype_ver_bounds[H5F_HIGH_BOUND(f)])
+        HGOTO_ERROR(H5E_DATATYPE, H5E_BADRANGE, FAIL, "Datatype version out of bounds")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5T_set_latest_version() */
+} /* end H5T_set_version() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Tcommit.c b/src/H5Tcommit.c
index c28b508..76d1b0c 100644
--- a/src/H5Tcommit.c
+++ b/src/H5Tcommit.c
@@ -327,9 +327,9 @@ H5T__commit(H5F_t *file, H5T_t *type, hid_t tcpl_id, hid_t dxpl_id)
      * a named type should always succeed.
      */
     if(H5T_STATE_NAMED == type->shared->state || H5T_STATE_OPEN == type->shared->state)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "datatype is already committed")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "datatype is already committed")
     if(H5T_STATE_IMMUTABLE == type->shared->state)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "datatype is immutable")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "datatype is immutable")
 
     /* Check for a "sensible" datatype to store on disk */
     if(H5T_is_sensible(type) <= 0)
@@ -343,15 +343,13 @@ H5T__commit(H5F_t *file, H5T_t *type, hid_t tcpl_id, hid_t dxpl_id)
 
     /* Reset datatype location and path */
     if(H5O_loc_reset(&temp_oloc) < 0)
-	HGOTO_ERROR(H5E_SYM, H5E_CANTRESET, FAIL, "unable to initialize location")
+        HGOTO_ERROR(H5E_SYM, H5E_CANTRESET, FAIL, "unable to initialize location")
     if(H5G_name_reset(&temp_path) < 0)
-	HGOTO_ERROR(H5E_SYM, H5E_CANTRESET, FAIL, "unable to initialize path")
+        HGOTO_ERROR(H5E_SYM, H5E_CANTRESET, FAIL, "unable to initialize path")
     loc_init = TRUE;
 
-    /* Set the latest format, if requested */
-    if(H5F_USE_LATEST_FLAGS(file, H5F_LATEST_DATATYPE))
-        if(H5T_set_latest_version(type) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set latest version of datatype")
+    if(H5T_set_version(file, type) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set version of datatype")
 
     /* Calculate message size infomation, for creating object header */
     dtype_size = H5O_msg_size_f(file, tcpl_id, H5O_DTYPE_ID, type, (size_t)0);
@@ -362,15 +360,15 @@ H5T__commit(H5F_t *file, H5T_t *type, hid_t tcpl_id, hid_t dxpl_id)
      * type message and then give the object header a name.
      */
     if(H5O_create(file, dxpl_id, dtype_size, (size_t)1, tcpl_id, &temp_oloc) < 0)
-	HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to create datatype object header")
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to create datatype object header")
     if(H5O_msg_create(&temp_oloc, H5O_DTYPE_ID, H5O_MSG_FLAG_CONSTANT | H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, type, dxpl_id) < 0)
-	HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to update type header message")
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to update type header message")
 
     /* Copy the new object header's location into the datatype, taking ownership of it */
     if(H5O_loc_copy(&(type->oloc), &temp_oloc, H5_COPY_SHALLOW) < 0)
-	HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy datatype location")
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy datatype location")
     if(H5G_name_copy(&(type->path), &temp_path, H5_COPY_SHALLOW) < 0)
-	HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy datatype location")
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy datatype location")
     loc_init = FALSE;
 
     /* Set the shared info fields */
@@ -399,12 +397,12 @@ done:
         if((type->shared->state == H5T_STATE_TRANSIENT || type->shared->state == H5T_STATE_RDONLY) && (type->sh_loc.type == H5O_SHARE_TYPE_COMMITTED)) {
             if(H5O_dec_rc_by_loc(&(type->oloc), dxpl_id) < 0)
                 HDONE_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to decrement refcount on newly created object")
-	    if(H5O_close(&(type->oloc), NULL) < 0)
+            if(H5O_close(&(type->oloc), NULL) < 0)
                 HDONE_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, FAIL, "unable to release object header")
             if(H5O_delete(file, dxpl_id, type->sh_loc.u.loc.oh_addr) < 0)
                 HDONE_ERROR(H5E_DATATYPE, H5E_CANTDELETE, FAIL, "unable to delete object header")
-	    type->sh_loc.type = H5O_SHARE_TYPE_UNSHARED;
-	} /* end if */
+            type->sh_loc.type = H5O_SHARE_TYPE_UNSHARED;
+        } /* end if */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Tprivate.h b/src/H5Tprivate.h
index f2da62e..2a47df3 100644
--- a/src/H5Tprivate.h
+++ b/src/H5Tprivate.h
@@ -134,7 +134,7 @@ H5_DLL herr_t H5T_vlen_get_alloc_info(hid_t dxpl_id, H5T_vlen_alloc_info_t **vl_
 H5_DLL htri_t H5T_set_loc(H5T_t *dt, H5F_t *f, H5T_loc_t loc);
 H5_DLL htri_t H5T_is_sensible(const H5T_t *dt);
 H5_DLL uint32_t H5T_hash(H5F_t * file, const H5T_t *dt);
-H5_DLL herr_t H5T_set_latest_version(H5T_t *dt);
+H5_DLL herr_t H5T_set_version(H5F_t *f, H5T_t *dt);
 H5_DLL herr_t H5T_patch_file(H5T_t *dt, H5F_t *f);
 H5_DLL herr_t H5T_patch_vlen_file(H5T_t *dt, H5F_t *f);
 H5_DLL htri_t H5T_is_variable_str(const H5T_t *dt);
diff --git a/src/H5trace.c b/src/H5trace.c
index 930002f..56fb472 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -1017,10 +1017,16 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                                     fprintf(out, "H5F_LIBVER_EARLIEST");
                                     break;
 
+                                case H5F_LIBVER_V18:
+                                    fprintf(out, "H5F_LIBVER_V18");
+                                    break;
+
                                 case H5F_LIBVER_LATEST:
                                     fprintf(out, "H5F_LIBVER_LATEST");
                                     break;
 
+                                case H5F_LIBVER_ERROR:
+                                case H5F_LIBVER_NBOUNDS:
                                 default:
                                     fprintf(out, "%ld", (long)libver_vers);
                                     break;