As Silva61 says, it will work without the update as the barcode doesn't appear to change thus letting you through the turnstile at the ground. This has happened for me, family and friends a couple of times since we returned after the World Cup.
Also on two other occasions, I have gone into my City site account, clicked on 'Season Tickets/Cards' and found the box that identifies my season card with the Google Pay app was 'unticked' for whatever reasons (nothing I had done to it!). Just clicked on it again and it refreshed the ticket info immediately to the correct game.
Hope you get sorted ASAP.