I’ve finally upgraded my site to the new Mambo 4.5.2.1 (yep, patched it
too :-).
So far it has been smooth sailing, just with a small glitch with Firefox caching some .js files, but that was solved with a simple Firefox restart, and because I have the SessionSaver extension, I was back where I left.
If all software upgrades were as simple and smooth as this one.