....and for you guys that like to collect old stamps, tickets, etc below are all prior year Metro Tickets used in CDMX. If you arrive before they go totally electronically maybe save one for old-time's sake

https://www.metro.cdmx.gob.mx/boletos-de-aniversario

And until all the Metro Stations all get set up totally electronically, many are using the metro card readers and may already be able to accept bank cards. But, the tickets are certainly going away by January 2024.