Andreas Kupries and Jeff Hobbs try to keep pointers to such on the SourceForge release area (see [L1 ]).
ActiveState has pages for versions
KJN I have retrieved a number of old versions of Tcl 6.x and matching versions of Tk by FTP from old mirrors. Tarball is at [L5 ] (7.0Mb). The tarball contains these versions not available from SourceForge: Tcl 6.1 and 6.5; Tk 2.2, 2.3, and 3.0; and assorted patches. Also alleged DOS ports for Tcl 6.2 and 6.7.
AK: Anybody who has versions of Tcl not found in Tcl's SourceForge release area please notify either me or Jeff Hobbs of this, and where to find them, to allow us to get them for the SF collection. I now have copied KJN's tarball and hope to have time to put them up soon.
The old Sprite distributions should have a very early Tcl. (Tcl and Tk were originally available by FTP from the hosts sprite.berkeley.edu and barkley.berkeley.edu; these hosts have long been disconnected. John Ousterhout's Sprite network operating system project [L6 ] ended several years ago.)
The oldest version at SourceForge is Tcl 2.1.
See also