In the past while addons.mozilla.org (AMO) would indicate an add-on was not compatible with the user’s version of Firefox, it would still allow the user to try and install the incompatible add-on. The user would get a warning that the add-on is likely not to work with their current version of Firefox and they could click a button again to go through with the download/install process. Unless the user had add-on compatibility checking disabled, Firefox would generate an error saying the add-on could not be installed.
So if an add-on won’t work with the user’s current version of Firefox, why even give them the option to try and install? The main reason for this was for people who are testing developmental versions of Firefox and needed the ability to install add-ons that were not yet marked as compatible with the newer version of Firefox. Around 95%+ of add-ons that work with Firefox 4 will work with the newer versions (up through Firefox 7, more on this in a future post) without the extension developer needing to do anything on their end other than bumping the MaxVersion variable (the latest version of Firefox the extension will work with). However, for the average user it caused confusion and frustration having the ability to install an add-on which says it will not work with their version of Firefox.
To address this AMO is going to change the way incompatible add-ons are displayed in the category pages and search results. With the newer version of AMO an incompatible add-on will show dimmed in the list and there will not be an install button. This is going to make things easier for regular Firefox users. But, what about those of us who want to use the Nightly, Aurora or Beta builds? If the add-on developer hasn’t yet bumped up their MaxVersion, how are we to install these add-ons? In the past we have talked about the Add-on Compatibility Reporter extension. The benefit of this extension is it automatically makes the needed about:config tweaks in regards to add-on compatibility checking, plus it gives the user the ability to report back directly to Mozilla if an add-on is compatible with the version of Firefox they are presently using. With the upcoming changes to AMO, users who have the Add-on Compatibility Reporter extension installed will see incompatible add-ons displayed normally and will have the ability to install said add-ons. There will be a warning message below the install button saying it may not work X version of Firefox, but they will be able to install.
The nice thing about this change is it going to keep non-advanced Firefox users from wasting their time and becoming frustrated trying to install incompatible add-ons. With AMO as it is designed now, even though an addon is not compatible, it will still has the ‘Add to Firefox’ button allowing the user to try to install the incompatible add-on. It has no way of differentiating between a user who has add-on compatibility checking disabled and those who do not. Under new the new system, only those users with add-on compatibility checking disabled (mainly advanced users) will have the ability to install an add-on that has been identified incompatible with the version of Firefox they are running.
This is a work in progress and will be rolled out in a future AMO update.
Source: Mozilla Add-ons Blog