[theamk]

literally the first point of parent post was:

> if a container is running for the current user, execute firefox in its context

So there is no need for snap to fancy serialization, just have new and old firefox ready, and keep using old one while it has running processeses. And if the old one exits for any reason, start new one instead.

That's all snap has to do! But it does not, because it really likes to make strange texhnical decisions for some reason.

(For "coordination", snap could make a common file in old app dir like "bin/new_version_availablec, and if firefox detects it, it shows that "your browser needs to be updated" button. I would not be surprised if something like this already exists in firefox. But I doubt snap would use this approach because it is not complex enough for it :) )