https://symbolcountdown.com/

March 12th snapshot date.

Snapshot Block

3,105,500

March 15th Symbol release date.

List of exchanges supporting opt in, snapshot, airdrop.

https://forum.nem.io/t/exchanges-that-have-announced-xym-support/26386

Quote

XEM deposits and withdrawals will be suspended starting from 2021-03-11 11:00 PM (UTC).

The future of Symbol (XYM) is unknown but the Symbol public blockchain will be launched on 15 March 2021.
Symbol platform. It is a migration from NEM to Symbol and you must know of The 3 essential things you need to know to claim your XYM.