Photo images now support read/write in the PNG format, with the ability to set the alpha channel.
New command tk busy is a variant of blt::busy that lets the interactivity of windows be suspended and restored as required by the needs of the program.
New command tk fontchooser provides a portable interface to the standard font selector of the platform, whether that is modal or not.
New option -angle $degrees to $canvas create text for rotating displayed text.
New commands $canvas moveto, $canvas imove and $canvas rchars for moving and manipulating canvas items.
Text widget cursor control, more window manager hints, and a collection of modernizations in appearance and function. See Changes in Tcl/Tk 8.6 or TIP #311 for the complete list.