Editing XPI files to get rid of some version restrictions in Firefox-extensions

Not much time passed after I posted my previous entry about using Firefox 3 Beta 2 as my main browser until I realized that while I had browsed around for almost a day without much trouble, I hadn’t used Ajax heavy sites such as Facebook and WordPress’ admin interface.

As soon as I started using modern, flashy sites in an interactive way, trouble with blank pages and elements such as text editors not loading, grew from being occasional, to irritating enough to make me upgrade to the latest trunk release of “Minefield 3.0b3pre”. These builds, I’ve used two so far thanks to autoupgrading, work much better than Beta 2.

CSLite‘s XPI-installer (version 1.3.5) had to be edited to install on the trunk build. XPIs are are zip-archives, which means that it’s trivial to extract, edit and add a new install.rdf to the archive to get rid of some version restrictions in XUL programs that use “Firefox-like” extensions.

I changed line number 63 in install.rdf to the following

<i:maxversion>4.0b2</i:maxversion>

What the value is changed to doesn’t really matter (now, that’s a lie), one would just want it to be higher than 3.0b2. Backing up your Firefox profile before doing things like this is of course a good idea, but breakage is in my experience most unusual, at least if the restrictions made in install.rdf are artificial and you don’t do anything more stupid to your Firefox profile.

I have a copy of my edited CSLite 1.3.5 for use on my own systems, but I’m not a trusted source and my copy is most likely outdated by now, and the issue I’m describing irrelevant, so get your own copy.