While it used to be possible to disable add-on compatibility checking entirely, by setting the extensions.checkCompatibility preference to false, it is now necessary to set a different preference for each new application version.
Disable Add-on Compatibility Checks is a Firefox, Thunderbird and SeaMonkey extension that re-enables the functionality of extensions.checkCompatibility irrespective of the current application version and disables checking by default. Checking can be re-enabled by disabling the add-on (which can be done without a restart) or by toggling the preference.
How to Install in Thunderbird:
1. Right-click the link below and choose "Save Link As..." to download and save the file to your hard disk.
2. In Mozilla Thunderbird, open Add-ons from the Tools menu.
3. Click the Install button, and locate/select the file you downloaded and click "OK".
No restart required!
- Shave 200ms off startup time.