Sorry all - I thought the OP had all NEW one day tickets that were going to be upgraded.
Yes, definitely, if they have been used and are more than 14 days old, they are not upgradeable.
Similarly, even if they are less than 14 days old, you can never put more than 10 total days on them (not what a PP said about only upgrading once - you can upgrade multiple times, but all within the 14 day windows and never to add more than 10 days to any ticket).
OP - if you have old non-expiring tickets, you can only use them as is.