I think 3.4.9 is more like a legacy stable version, even if it's a little old.
We should not add any new feature to this branch, but we can still improve stability (especially minor corrections like this one)
It would be nice to release a stable SB version working with a stable 3.4.9 branch.
And then switch to your 3.5 branch, which is still untested. It needs time to get adopted, you made some modification in the core, dev must adapt their project or read a clean documentation (for exemple explaining why this modification you made is a good idea: https://github.com/cocos2d/cocos2d-objc/issues/1361 - I personaly have no opinion on this)