Update to legacy XUL version of add-on for Firefox ESR 52.x and Thunderbird rejected due to migration to WebExtensions

My extension is compatible with both Firefox and Thunderbird. I’ve released a new version (numbered 6.0.x) that was rewritten as a WebExtension so that it is compatible with Firefox 57 and newer, but I need to release an update to the XUL legacy version (numbered 5.5.x) to maintain support for users on Firefox ESR 52.x and Thunderbird. The 5.5.x update was rejected by the Mozilla Add-ons reviewer due to the policy of not permitting updates to legacy add-ons once they have been migrated to WebExtensions. Given that I still need to support users on Firefox ESR as well as Thunderbird (which isn’t moving to WebExtensions), how do I release a legacy version for those users on Mozilla Add-ons?

You can still upload addons for Thunderbird, FF *-56 and ESR. The problem is the system doesn’t allow multiple systems (WE & legacy) under the same ID.

The option is to create a new entry for one of them (WE version or the legacy version). It will be inconvenient since there is no automatic method of transferring users to the new addon.

That is all I can think of. Maybe @jorgev has a better suggestion.

I think you can submit a legacy version as long as its compatibility information only supports Thunderbird. If that doesn’t work, we can try to help you using an admin override.

This is only temporary, since we’re working on migrating Thunderbird add-ons to a different location and this problem will be gone.

Jorge, I can try to resubmit, but I’d rather not leave behind my Firefox ESR 52.x users, as there are quite a number of them, according to the statistics for my add-on. Would it help if I set the maxVersion for Firefox to 56.*?

I think that if you set the maxVersion to 56.* and set the strictCompatibility flag in the manifest, it will be accepted. If that doesn’t work, we can help you make it work.

Thanks Jorge! I’ve submitted my updated legacy add-on with the addition of the strictCompatibility flag in the install manifest.

@jorgev - I will need your help to get approval for the legacy XUL update to my add-on, Clippings. It was rejected again, despite adding the strictCompatibility flag to the manifest and setting maxVersion to 56.*.