I do most of my VBA in Excel and yes, calls and some functions do change (mostly added new ones.) The basis for all versions is very stable, in many of my applications I've been able to move from VBA6 to VBA5 without re-writing the code.
120666: I wrote several hundred lines of VBA code back in 1999 on what was probably then an outdated version of excel - running a model, swapping data from worksheets to arrays and back, plotting results etc... I was pleasantly surprised to fire it up on a whim the other day and see the whole thing execute perfectly on v2003.
At work, we still have Excel sheets that have macros listed on separate sheets (originally created in Excel version 5 - 1993). These still work as originally designed, although the code is much different than what would be required for an identical task in the current version.
