Released April 6, 2001
New packages
New default
Expanded syntax/new options
expr {![set a on]}
scan [format %o -1] %o v; # $v == -1
scan [format %x -1] %x v; # $v == -1
wm iconbitmap window ?-default? ?image? (Windows)
Improved performance
A historical look at a discussion of tcl 8.3.3 vs 8.4 plans can be found in Tcl 8.3.3 Plans.