How to target last 2 versions of FF ESR?

How can I target the last 2 versions of FF ESR? If I use last 2 versions, I only get FF 52 and 53; I would expect to get FF 45, 52, 53:

• 53 is latest FF
• 52 is previous version of FF, plus latest FF ESR
• 45 is previous FF ESR

Using the demo at http://browserl.ist it does not seem possible to write a query that pulls in “the last two versions of Firefox ESR”.

This is important because there’s always a qualification period during which the previous ESR version and the next ESR version overlap, so they’re both active and supported for a time (such as right now). Also, institutions/enterprises are notoriously slow to upgrade, so it would be nice to be able to target N versions back, based on the target audience.

[ZebraFlesh]

Why selecting it y version Firefox 42, Firefox 38 doesn’t fit your needs.

Because I want to use a semantic query string such as “last N versions”. Using hard coded values means I need to update my list of browsers whenever there’s a new ESR release.

last 3 ESR versions also doesn’t have semantics reasons. ESR is supporting level. When Mozilla stop to support a version, it could not called ESR anymore.

Maybe this is our point of confusion. ESR is not just a support level: it is a distinct software baseline. Here’s the repo for ESR 45: https://hg.mozilla.org/releases/mozilla-esr45/ It is definitely a separate piece of software. When the Mozilla Foundation stops supporting a particular ESR release, the tag does not disappear from the repo. (Go up a level and you can go all the way back to the ESR 10 baseline.) It’s still an ESR, just an unsupported one – the same way that Microsoft no longer supports IE 8.

[ZebraFlesh]

It’s simple: organizations and enterprises are slow to upgrade and do not follow the Mozilla schedule. There’s likely a number of intranets that are still running ESR 38 because they haven’t upgraded their infrastructure. Those computers are locked down and cannot be autoupdated by users. Organizations running ESR 38 at this point are just a little slow and are just under a year out of date. That doesn’t seem like a good reason to punish those users.

I don’t think this requires a new version in the code. You’re already aliasing ESR to a particular Firefox version. Why not just alias it to a list and make it synthetic browser version in order to support the queries with browserlist? If you were tracking bugs, this wouldn’t be right; however, you’re tracking browser capabilities and ESR freezes those upon first release, so this approach sounds correct.

Most of developers don’t think about Firefox ESR as separated browser. So they will be surprised too see unsupported previous Firefox ESR in last 2 versions query (it loads all browsers, so with you suggestion it will load last 2 Firefox ESR versions too).

And I was surprised to see browsers that are primarily used in China (it’s not my target market). People will adjust the same way they did with how the 2.0 release changed the last 2 versions results.