Firefox 3.1 now 3.5 is now in the release candidate stage, but there has not been one update to Google Gears to support the beta, or RC. The final version should be released soon, but there is no indication that Gears will be ready for the release. I think this quite frustrating. Especially because I've been using the beta forever.

You could go to about:config, add the boolean "extensions.checkCompatibility" and set it to false. This will disable the compatibility check, but I don't know if it will really work well, since Gears is a complicated extension.

Apparently a fix is coming soon:
groups.google.com/group/gears- ...

The compatibility check hasn't worked before with Gears. Hopefully they can get this out before the final release.