....does such a list of changes exist, particularly breaking changes?

Case in point is that the Value property for a Range was changed from
"plain" to "parameterized" (by XLRangeValueDataType) in recent Excel's, and
constructs like "obRange.Value(1, 1)" which worked in excel 97/2000 now fail
in 2002/2003 with a compile error because "(1, 1)" is now parsed as
parameters for the Value property instead of indexes into the Value array.

There are workarounds, of course, like using .Cells(1, 1).Value, or using
Value2 which hasn't changed in recent versions. Yet, as just an occasional
Excel user, I am still ticked off that an .xls which works fine in 97/2000
had to be changed many years after the fact in order to accommodate a
trivial, but compatibility-breaking, object change.

Worse, I have some other old .xls's and, short of such a "breaking changes
log" which I haven't found yet, I can't be sure what else may be broken - or
different - now. It was lucky in a sense that the Value change caused a
compile error in this case, which was relatively easy to track down. Should,
for example, Value be parameterized with two arguments in the next version
of Excel, the old code might well compile again, but do something entirely
bogus, and then _that_ would be funny to figure out.

Thanks,
Liviu