According to ETC official information, ETC will be hard forked at a blockchain height of 5,900,000. The main update from this hard fork is removal of the difficulty bomb and will not generate new coins.
To ensure security of users' assets, Huobi Pro will suspend ETC deposit and withdrawal at 23:00 on May 29th, 2018(GMT+8). We will resume ETC deposit and withdrawal promptly when ETC runs stably after the hard fork. Please find the specific time in our announcement. We apologize for any inconvenience caused by this.
ETC official announcement: https://ethereumclassic.github.io/blog/2018-03-12-etc-roundup/
May 29th, 2018