core (for now), and release the
In my mind there has to be a way to convert the snapshots. Maybe ship
qemu from both 16.04 and 18.04 in a same snap? One of them could be statically linked. In any case, once you know exactly how you want to transition your users from the old world to the new, you can release a transitional
epoch: 1* snap to
beta that implements that. Once most of your users in beta are on that, you can release
epoch: 1 snaps to beta.
What isn’t released is the stepping of an upgrade through epochs in a single refresh. Stepping slowly already works. If a user is on
epoch: 0) and tries to do
snap refresh --candidate to something that has
epoch: 1 and there is an
epoch: 1* somewhere in the channel history to bounce through, the refresh will end up on that revision (with a warning about the
candidate being closed), and then a later auto-refresh (or a manual
snap refresh) will get them to the wanted revision.