My biggest complaint is that every time they change some tiny something in Firefox in order to claim it’s a new version, your extensions and themes are broken. I’ll wait a while before checking this one out.
Maybe, maybe not. An extension can be "broken" in one of two ways:
1) It can simply not be compatible with the new version. But this is not always the case.
2) The author put a version as the maximum version it will run on, even though it will run on later versions. Firefox respects this max version flag (there's a min version one too), and won't run it if the version is outside of the range.
I can give you instructions for how to modify extensions to increase the allowed version. You only need Notepad and a compression utility that can work with .jar files. No guarantee the extension will actually work with the new version, as in #1 above.