I just downloaded the latest IntelliJ (#IC-141.713.2) and ran it. Then I ran my old version (#IC-141.178.9) again. When I started the old one up, I got messages about not being able to find my color schemes in dialog boxes. Here's the log entry:
2015-05-01 13:57:52,357 [ 4295] INFO - ions.SchemesManagerFactoryImpl - Cannot read scheme Andrew.icls from '$ROOT_CONFIG$/colors': Unsupported color scheme version: 141
java.lang.IllegalStateException: Unsupported color scheme version: 141
Then I ran the new version again, and there were no warning messages, but my schemes were still gone! There were some other errors in the logs; not sure if they are relevant:
2015-05-01 14:00:01,495 [ 34559] INFO - vaFunctionalExpressionSearcher - #files: 67
2015-05-01 14:00:03,489 [ 36553] ERROR - ferenceCompatibilityConstraint - Assertion failed
So then I went into my .IdeaIC14/config directory, and there was no colors directory! It was completely gone (it wasn't empty - it didn't exist). My keymap customizations survived.
Obviously, I should have been backing up my config directory, but I'm so frustrated that all my customizations are gone. I know there's nothing to be done to get them back, but I thought you might like to know in case there's something you could fix for the next person to try this.