changelogs?

Okay, I was using 2.3.1 and just installed 2.4.1.

I had 2.3.1 customized to match the theme of my site.

My Question is...

Are there "update" files available, where one can just edit the source code from 2.3.1 to the current version, the same way as you would add a mod or update phpbb from 2.0.16 to 2.0.17???

Like so.....

I think it would be WAY EASIER to edit a few changes rather than trying to recode each & every file all over again to customize it the way it was before.

Carbonize ?

I assume your customisations are only theme based. The only changes to templates I am aware of are to add $CAPTCHA variable to form.php and add the actual captcha template.