Tcl/Tk 8.7a5 Release Announcement
June 18, 2021

The Tcl Core Team is pleased to announce the 8.7a5 releases of the Tcl
dynamic language and the Tk toolkit.  This is the third alpha release
of Tcl/Tk 8.7.  More details can be found below.  We would like to
express our gratitude to all those who submit bug reports and patches.
This information is invaluable in enabling us to identify and eliminate
problems in the core.

Where to get the new releases:
------------------------------

Tcl/Tk 8.7a5 sources are freely available as open source from the
Tcl Developer Xchange web site at:

        http://www.tcl-lang.org/software/tcltk/8.7.html

This web page also contains additional information about the releases,
including new features and notes about installing and compiling the
releases.  Sources are always available from the Tcl SourceForge
project's file distribution area:

        http://sourceforge.net/projects/tcl/files/

This distribution is source code only.  We keep links to some third
parties offering pre-built binaries for various systems here:

	http://www.tcl-lang.org/software/tcltk/bindist.html

For additional information:
---------------------------

Please visit the Tcl Developer Xchange web site:

        http://www.tcl-lang.org/

This site contains a variety of information about Tcl/Tk in general, the
core Tcl and Tk distributions, Tcl development tools, and much more.

Summary of Changes since Tcl/Tk 8.6.11 and 8.7a3:
-------------------------------------------------

These are alpha releases of 8.7.  The alpha designation means that 
they are in a period of feature addition.  All relevant bug fixes (and
some more) up to and including changes in 8.6.11 are included in 8.7a5.
The following list focuses on new features added to 8.7a5 since 8.7a3. The
changes file at the root of the source tree contains a more complete
list.  The Timelines of all changes are online.

	https://core.tcl-lang.org/tcl/
	https://core.tcl-lang.org/tk/

This release is a development release, and should only be considered for
deployment use after considerable testing.  

New Commands and Features
   * [TIP 542,575] Support for switchable Full Unicode support
   * [TIP 597] [string is unicode] and better utf-8/utf-16/cesu-8 encodings
   * [TIP 588] Unicode for (X11) keysyms
   * [TIP 595] Unicode-aware/case-sensitive Loadable Library handling
   * [TIP 325] System tray and system notification
   * [TIP 529] Add metadata dictionary property to tk photo image
   * [TIP 584] Better introspection for ttk
   * [TIP 481] Tcl_GetStringFromObj() with size_t length parameter
   * [TIP 587] Default utf-8 for [source]
   * [TIP 565] Gracefully ignore non-existent tags in canvas raise/lower
   * [TIP 563] Scrollwheel on Horizontal Scrollbar Scrolls Without Shift
   * [TIP 591] Rotate ttk::notebook window with mousewheel on tab
   * [TIP 474] Uniform mouse wheel events
   * [TIP 551] Permit underscore in numerical literals in source code
   * [TIP 574] Add a 'tag delete' command to the ttk::treeview widget
   * [TIP 564] Specify ttk font sizes in points on X11
   * [TIP 586] C String Parsing Support for [binary scan]
   * [TIP 598] Tcl_WinConvertError
   * [TIP 580] Tk_GetDoublePixelsFromObj and 5 more
   * [TIP 585] INDEX_TEMP_TABLE flag for Tcl_GetIndexFromObj()
   * [TIP 582] Comments in Expressions
   * [TIP 557] C++ support for Tcl
   * 'end' argument to [$canvas insert]
   * Implement 64-bit seek on Zip channels
   * bind substitution %S
   * Drop TCL_WINDOW_EVENTS from Tcl's [update idletasks]
   * [chan truncate] for reflected channels
   * tzdata updated to Olson's tzdata2021a

Deprecations/Migration aids
   * [TIP 592] End support: Windows XP, Server 2003, Vista, Server 2008
   * [TIP 590] Recommend lowercase Package Names
   * [TIP 538] Externalize libtommath
   * [TIP 543] Eliminate `TCL_INTERP_DESTROYED` flag value
   * [TIP 559] Eliminate public routine `Tcl_FreeResult`
   * [TIP 562] Deprecate channel types 1-4
   * [TIP 578] Death to TCL_DBGX
   * [TIP 569] Eliminate Comments That Serve Lint
   * Restore Tcl [update] when Tk is destroyed
   * Solve XKeycodeToKeysym deprecation
        *** POTENTIAL INCOMPATIBILITY -- Tk 8.7 now requires X11R6 ***

Fix crashes or hangs in ...
   * [string index abcd 0-0x10000000000000000]
   * [set l {}; lpop l]
   * tests binary-79.[12]
   * [fconfigure stdout] on Windows
   * Tcl_Unload()
   * SVG memory overflow
   * [tkwait]
   * Aqua: dead keys as menu accelerator

Bug/Regression Repair
   * [chan postevent] revised to be event-driven, as name implies
        *** POTENTIAL INCOMPATIBILITY ***
   * [string trim*] on astral characters
   * deletion trace on imported ensemble
   * Aqua: double click bind with changing focus
   * Follow Mac OSX Key-repeat setting
   * update scrollbars on treeview

--
Tcl Core Team and Maintainers
Don Porter, Tcl Core Release Manager