BitMEX Research previously released Twitter that BCH will perform a hard fork upgrade at block heights of 609,135. The monitoring data shows that the BCH chain has reached the planned upgrade block height. Blocks 609, 315 are dug by AntPool; the current BCH chain block height has reached 609, 136, which was dug up by BTC.com. BitMEX Research subsequently issued a special statement that ForkMonitor has detected invalid blocks on the BCH and hard forks have been generated. Older versions of Bitcoin ABC, including version 0.19.0, will either remain the same or take another chain. Bitcoin ABC 0.19.0 determined that the chain was invalid, as expected when the hard fork was upgraded.