So a hard p2pool fork?
Sorry I guess I'm just too used to BTC devs running screaming every time a hard fork is mentioned ... so I didn't think that's what you were referring to.
Most of the p2pool upgrades that I've seen are hard forks
It's less severe than a bitcoin hard fork because worst case, you are just left solo mining. It's not like you are on a different bitcoin blockchain and can't spend your money anymore.
Except that all your unpaid shares are worth nothing once the fork disappears.