Every new +0.1 release of Mozilla Firefox or Mozilla Thunderbird extensions stop installing because they have too low maxVersion of targetApplication specified. Developers are sometimes slow in updating their extensions (or they are abandoned) and in the meantime you can't use your favourite extension.

Warning: The below tricks would only allow you to install the extension, there is no guarantee that it would work and it might even break your Mozilla application.
TEM Staff takes no responsibility for your usage of info covered in this tutorial although many of extensions after those changes should work as before.
It is adviced to test first on new profile before installing on to the default one.

There are two ways to get your old extension to install on the new version of Mozilla Firefox or Mozilla Thunderbird.

Method 1:
This method changes one setting in your Mozilla Firefox configuration. This is really easy and quick way to get your extension to install again.

- Start Mozilla Firefox
- Type about:config in the address bar
- Type "app.extensions.version" in the filter bar
- Right click the entry and choose modify
- Change the value to the version number of the Mozilla Firefox version you were using before updating
(e.g. you were using Mozilla Firefox 1.0.7 and the value now says 1.0+, change that value back to 1.0)

Notes:
- Lowering "app.extensions.version" would disallow you from installing extensions which min-ver exceeds the new value. (Bugzilla comment)
- With the latest nightlies (Mozilla Firefox Beta 2) you will have to create the "app.extensions.version" entry. Right-click anywhere and choose New -> String.

Method 2:
This method involves modifying the extension itself. You have to again change one value to allow your extension to install. This method might be a bit harder or take more time, but the benefit is that you end with an extension that you can give to others that have the same problem.

- Download the extension (You should end up with an *.xpi file)
- Open the downloaded *.xpi with any archiver (Winzip, Winrar, Izarc)
- Look for the file called install.rdf
- Open it with a plain text editor (Notepad, vim) (DO NOT use word, wordpad, etc)
- find the line that looks like <em:maxVersion>*</em:maxVersion> (Where * is a version number)
- change the version number to the version of your updated Mozilla Firefox
- Now save the install.rdf and update the archive (DO NOT use any form of compression)
- You have now "bumped" the extension and it will now install and probably work again

Notes:
- From Mozilla Firefox Beta 2 on its possible to bump the maxversion to 1.x.* where * will be treated as infinity. This will greatly reduce the need for a new bump.
Treat 1.5.* as 1.5.infinity

Method 3:
This method involves installing an extension, to re-enable the disabled incompatible extensions.

- Install Nightly Tester Tool
- Restart Firefox
- Now open the Extension Manager and rightclick a disabled incompatible extension.
- Choose the option "Make compatible"
- Restart Firefox and the extension will work again
Note: You can make several extensions compatible at once.

Guide coutersy of Sboulema of The Extension Mirror.



This post has been edited by evilhomura89: Nov 10 2005, 01:10 PM