Deprecating Monero's Custom Transaction Unlock Time

Please be advised, the Custom Transaction Unlock Time feature is set to be deprecated at consensus with FCMP++. There is already a relay rule in place today that prevents nodes from accepting and relaying transactions with a Custom Unlock Time to the transaction pool (source). This is a formal announcement that the feature would be deprecated altogether with the FCMP++ fork, and new transactions with Custom Unlock Time set would not be able to enter the chain even if a miner mines them.