Revert to the old version of amsmath?

[PlamenToby]

I updated the packages today and one of my latex files compiles with a bunch of errors I cannot fix. Is there a way I can go back to the old version of amsmath?

EDIT: I ended up reinstalling the whole package. I did not update the few optional updates and now it works.

By the way, apparently each package can be uninstalled and if you have a second computer with an older configuration, you can copy and past the folder from there (but this did not solve my problem).