There were no fork, the problem that Cryptopia used V5.4 and needs to re-sync their wallet! The main wallet was not changed too much - only POW which exchange doesn't use.
The chain is one - Cryptopia was stucked during implementation, now solving it with re-sync process.
The Cryptopia support is very fast with any kind of service, very good service!
CoinExchange didn't change anything, so they were on V5.3!