Firefox – convert an existing Firefox installation to ESR without a re-install

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It took some jumping through hoops (including a mailing list subscription that I apparently didn't need) but I finally found where to download the Firefox ESR. This is great for fresh installs, but I was wondering if there's a way to simply convert existing installations to the ESR configuration without having to do a full install.

As I understand it, the only difference between ESR and regular Firefox will be how they receive updates. After the new standard version of Firefox comes out, ESR releases will only receive critical security updates and bug fixes for the remainder of their support life. Newer versions of Firefox's standard build will have all the latest and greatest features, while ESR releases are meant to provide stability for environments that can't be expected to keep up with a new full version number change as often as Mozilla does them.

In regular Firefox, the About screen shows that I am using the "release" update channel.

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Is switching to ESR really just a matter of switching the update channel? I presume this can be done in about:config by changing app.update.channel and probably also app.update.url. However, I don't know what these values should be for ESR or if anything else should be tweaked.

So, is it possible to switch to ESR without a reinstall and, if so, how?

(Note: While this question was written originally for Firefox 10, I expect any answers will apply to future ESR versions as well.)

Best Answer

Converting to ESR is done in principle by updating in defaults\pref\channel-prefs.js this line :

pref("app.update.channel", "esr");

According to the mozillaZine thread Changing Your Update Channel, it's hard coded in the channel-prefs.js file, so changing in about:config will not work.

However, not every non-ESR version can be converted to ESR just by changing channel-prefs.js. The ESR version is entirely distinct from the normal version, even if the differences are very minimal for a given version, so one should use the released ESR version. Even if updating channel-prefs.js works for the some version such as Firefox 10.0, there is no guarantee that this will work for the next ESR version.

This is clearly shown in the article Enterprise/Firefox/ExtendedSupport :

image

You can see from the above image that not every Firefox version has a corresponding ESR version. There are much fewer ESR versions than "normal" ones. The article also says that testing if a new ESR version fits the needs of your organization is your responsibility.

Because of all these differences, I would advice against converting an existing Firefox installation to ESR, but would rather start from a clean ESR installation.

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