why there are no diff-patches?

[kilburn]

It's not that easy.

When updating, we have to update the version number in ispcp at the very least. Additionally, updates (even "just some fixes such as this last release") also carry binary files (images for pma). These are just two quick reasons I've able to think just now, but I'm quite sure there are more.

Nevertheless, if you want to patch there's noone preventing you from going to the correspondent revision logs in trac, fetching unified diffs and manually applying them.