Version 0.6.3 of the User Agent Switcher extension has been released. The full history is available, but the two main changes in this release are the hiding of the option to automatically reset the user agent when the browser closes and the addition of support for update notifications.
The reset option has been hidden because too many people were disabling it without reading the FAQ and understanding why it was enabled by default. If you understand the problem and still want to disable the auto reset functionality then just manually set the preference ‘useragentswitcher.reset.onclose’ to ‘false’.
Mozilla Update development is apparently continuing, but in the meantime they are not accepting extension submissions via Bugzilla and I cannot do the updates myself until the developer section is activated. This is frustrating, to say the least, therefore I have changed the User Agent Switcher extension so that it no longer uses Mozilla Update to check for updates. Going forward Firefox should indicate immediately when a new version has been released. I will be making the same change in the next release of the Web Developer extension.