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Tcl/Tk 8.6.18 Release Announcement
May 11, 2026

The Tcl Core Team is pleased to announce the 8.6.18 releases of the Tcl
dynamic language and the Tk toolkit.  We intend these to be the final
releases of Tcl 8.6 and Tk 8.6.  Both Tcl and Tk have successor major
release sequences in active supported development.  As of this release
date, users of Tcl and Tk are encouraged to move to Tcl 9.0.3 and Tk 9.0.3.

With development of Tcl/Tk 8.6 at an end, we are no longer soliciting
bug reports and patches for these lines of development.  Please only
report issues that are believed so severe in nature that they would
justify re-opening a closed development sequence.

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

Tcl/Tk 8.6.18 sources are freely available as open source 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

Tcl/Tk 9 releases:
------------------

The latest stable releases of Tcl and Tk are versions 9.0.3, released
November 13, 2025.  Users of Tcl/Tk 8.6 are encouraged to migrate to the
new releases, where continued development efforts are focused.

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 8.6.17:
--------------------------------------

This is a patch release, so it primarily includes bug fixes and corrections
to erratic behavior.  Highlighted changes are noted below.  The changes file
at the root of the source tree contains a more complete list.  The Timelines
of all changes are online.

	http://core.tcl-lang.org/tcl/timeline
	http://core.tcl-lang.org/tk/timeline

    * Tk support for the macOS major version renumbering

    * X11 support for Copy/Cut/Paste keys

    * Fix crashes or hangs or undefined behavior in...
       - crash on exit due to faulty asm code in DllMain
       - [frame .f -class]
       - [.text sync -command {puts 1}; .text sync]
       - [wm forget [menu .m]; tk_popup .m 100 100]
       - proc creation during namespace deletion
       - menu.test during a -singleproc 0 run of Tk test suite
       - Tcl_PushVarName()
       - SetScriptLimitCallback()
       - ImgGetPhoto(), XCreateBitmapFromData()
       - Tk_GetFromFromObj()
       - RefocusGrabWindow() on Aqua

    * Improve -blockcursor so that text contents are not obscured.

    * X11 error when Xft fonts for 24-bit depth are used by 32-bit visual.

    * Don't let empty regexp suppress errors of variable resolution

    * Don't let [string trim] produce invalid utf-8.

    * Prevent menu cascade loops.

    * Prevent re-entrancy troubles in ButtonUp handler for spinbox.

    * Installation on Windows now includes manpages and pkg-config.

    * Updated bundled packages, libraries, standards, data
       - Itcl 4.3.7
       - sqlite3 3.53.0
       - Thread 2.8.13
       - TDBC* 1.1.13
       - platform 1.1.0
       - http 2.9.9
       - tcltest 2.5.11
       - dde 1.4.6
       - tzdata 2026b
       - Unicode 17
       - zlib 1.3.2
--
Tcl Core Team and Maintainers
Don Porter, Tcl Core Release Manager

-- 
| Don Porter            Applied and Computational Mathematics Division |
| [email protected]             Information Technology Laboratory |
| http://math.nist.gov/~DPorter/                                  NIST |
|______________________________________________________________________|