According to the NEM (XEM) team, the “Harlock hard” fork will take place at block# 3,464,800, estimated at 18:00 UTC on 18 November 2021.

Gate.io supports this upgrade and will suspend NEM (XEM) deposits and withdrawals during the process. Deposits and withdrawals will be resumed as soon as possible after this upgrade. NEM (XEM) trading will not be affected.
Thank you for your understanding and continued support.
The hardfork for NEM is intended for users to explicitly signal support for the integration of NEM as a dedicated subChain of Symbol

Learn more:
https://hackmd.io/@syndicate/harlock