Compatibility with Firefox ESR
In April 2011, Mozilla began releasing new versions of Firefox on a more rapid release schedule. This is good news for users but makes things bit more complicated for organizations unable to upgrade Firefox for all their users so quickly. As a result, there is now an Extended Support Release (ESR) version of Firefox which evolves more slowly.
At this time Firefox ESR is not something we officially support. We are investigating ways to support it through official means, but as of right now your best bet is to use a previous version of the extension. Until there is official support, it is possible that a change to the ESR version of Firefox will break this functionality at any time. That said, we offer a step by step guide to installing 1Password in Firefox ESR.
How To: Use 1Password with Firefox ESR
Geeky Details
The current version of Mozilla's JetPack SDK is only supported in newer versions of Firefox. It is not possible to support Firefox 10 ESR and stay current with the JetPack SDK at the same time. It is likely that 1Password is not the only extension affected by this.
As mentioned above, we are investigating a different way to approach this, so that an ESR version of the 1Password extension may be possible, which will disable the updates that the stable version of the 1Password extension will get. There are security implications, however, that we must consider if supporting ESR in this way (e.g., the main 1Password application may require a newer extension that may not work well with Firefox ESR).
If we can be of further assistance, please post a new thread in the Browser Extensions Forum so we can help.