Newer releases of Ubuntu can always start making use of new file system feature flags. Looking at all currently supported releases (whether standard or ESM), we have never SRUed e2fsprogs before, it only ever received security updates, so I'd be inclined to not do a backport here either and resolve that in the snap side of things.
Generally for recovery purposes you will be booting an image with an equal or newer version of Ubuntu.
Regarding Dimitri's comment about new kernel feature support in 5.15, that doesn't seem related to this issue, and I'm not sure we should be changing feature flag in a stable release anyhow.
Newer releases of Ubuntu can always start making use of new file system feature flags. Looking at all currently supported releases (whether standard or ESM), we have never SRUed e2fsprogs before, it only ever received security updates, so I'd be inclined to not do a backport here either and resolve that in the snap side of things.
Generally for recovery purposes you will be booting an image with an equal or newer version of Ubuntu.
Regarding Dimitri's comment about new kernel feature support in 5.15, that doesn't seem related to this issue, and I'm not sure we should be changing feature flag in a stable release anyhow.