Pedro, ancestor is working on the next update. No idea when it'll be ready though.
If you seriously need a compatibility bump, you have four ways:
1) Wait for ancestor's next update.
2) Manually bump the maxVersion in Brief's install.rdf file. You will have to repackage Brief into an .xpi or .jar file and reinstall your manually bumped Brief. You'll find Brief's extension files in the extensions folder of your current profile. You should back up your profile folder before messing with any of the contents inside.
3) Use the Add-on called Nightly Tester Tools (provided it too is compatible) to force Brief's compatibility.
4) Disable Firefox's compatibility checker. (*- Will also activate other disabled incompatible add-ons at the same time, so use at your own risk.)
EDIT - I've did a manual bump for Brief (1.2b2) and it's working just fine in FF3 RC 1 (Windows XP).
Re: Brief 1.2 beta 2 available
Pedro, ancestor is working on the next update. No idea when it'll be ready though.
If you seriously need a compatibility bump, you have four ways:
1) Wait for ancestor's next update.
2) Manually bump the maxVersion in Brief's install.rdf file. You will have to repackage Brief into an .xpi or .jar file and reinstall your manually bumped Brief. You'll find Brief's extension files in the extensions folder of your current profile. You should back up your profile folder before messing with any of the contents inside.
3) Use the Add-on called Nightly Tester Tools (provided it too is compatible) to force Brief's compatibility.
4) Disable Firefox's compatibility checker. (*- Will also activate other disabled incompatible add-ons at the same time, so use at your own risk.)
EDIT - I've did a manual bump for Brief (1.2b2) and it's working just fine in FF3 RC 1 (Windows XP).