Rich Burridge wrote: >>And I forgot to give you this link: >>http://docs.python.org/whatsnew/whatsnew24.html >>> That lists the changes. It's not clear (at least to me) whether > these changes are incompatible. The section http://docs.python.org/whatsnew/node15.html is meant to cover incompatible changes. It shows that there is no 100% compatibility, but that only "borderline" code is affected. Probably the most significant change is that 0xC0000000 is now a positive number, when it used to be negative on 32-bit systems. Regards, Martin