With it showing 4/20 now it's likely because Cryptopia finally brought their wallets back online and are catching up with the network. It should be fine soon. Other exchanges (example: C-Cex) are working fine.
Cryptopia support replied the following when I asked when the maintenance will finish:
"It will be finish if and when the issue is resolved. As it appears the network has forked it will depend on the ORO devs/community to provide a solution to this. Thanks MrFloppy Cryptopia Team"So, what ORO developers can say about this?