Since Brexit, the rules for entering European countries within the Schengen Zone changed. This means that you need to be aware of both the issue date and expiry date on your passports. Older passports may have had additional time added to the expiry date when you received it (depending on how much time was left on your previous one).
European (Schengen Zone) passport validity requirements for British travellers:
- ISSUE DATE must be LESS THAN 10 years before the date you ARRIVE in the country
- EXPIRY DATE must be MORE THAN 3 months from the date you LEAVE the country
Further clarity can be found in the Entry Requirements section of your destination on the FCDO website: https://www.gov.uk/foreign-travel-advice