Sometimes it is helpful to know what the differences between releases of Tcl/Tk are. Perhaps you want to know how many releases back a feature is available. Perhaps you want to know "What's new?" since your reference book was published. These pages aim to quickly summarize the differences introduced in each release of Tcl/Tk which are visible at the script level. For further details, see the release announcements [L1 ] or the changes file in the Tcl/Tk distribution. Please expand/correct these pages as necessary. (Do I have to say that in a Wiki?)
Commentary on individual changes also appears in "Advantages and disadvantages of different Tcl versions".
See also: Tcl Benchmarks
2008 - See http://tip.tcl.tk/311 for plans for upcoming releases.