I have some tickets we used on our 2004 trip. They were 4 day park hoppers, but we didn't use the fourth day. Are they still valid for one day? I think I read somewhere that tickets bought before 2005 never expired.

Just wondering...thanks!

They should be (since it was before the MYW tickets which introduced the no-expiration option as an add on cost).

That is correct. Tickets issued prior to 1/2/05 normally had no xpiration.

However, those tickets cannot be modified or upgraded in any way.

If you want, take it to any ticket booth and they can check if for you; if there is any problem with the magnetic strip they will issue a new ticket with the same remaining entitlements on it.