The source code for Tk is managed by fossil. Tk developers coordinate all changes to the Tk source code at > [Tk Source Code](https://core.tcl-lang.org/tk/) Release Tk 8.7b1 arises from the check-in with tag core-8-7-b1. Highlighted differences between Tk 8.7 and Tk 8.6 are summarized below, with focus on changes important to programmers using the Tk library and writing Tcl scripts containing Tk commands. ## Many improvements to use of platform features and conventions. - Built-in widgets and themes are scaling-aware. - Improved support of two-finger gestures, where available - The `tk windowingsystem` "aqua" needs macOS 10.10 or later ## New commands and options - `tk sysnotify`: access to the OS notifications system - `tk systray`: access to the OS tray facility - `tk print`: access to the OS printing facility ## Widget options - New `ttk::progressbar` option: **-text** - `$frame ... -backgroundimage $img -tile $bool` - `$menu id`, `$menu add|insert ... ?$id? ...` - `$image get ... -withalpha ...` - All indices now accept the forms **end**, **end-int**, **int+|-int** ## Improved widget appearance - `ttk::notebook` with nondefault tab positions ## Images - Partial SVG support - Read/write access to photo image metadata