Upgrade which always resulted in "serial number not recognized" errors

[Richard Hinojos]

I purchased Nitro Pro in June 2019 and was fully expecting an upgrade to release 13.  My understanding is that Release 13 was on September 2019, a mere three months after my Nitro Pro purchase.  I have, over time, attempted the upgrade which always resulted in "serial number not recognized" errors.  This week I found out about key productivity features that exist in 13 that do not exist in 12.  I really think that I should NOT have to pay $89 for an upgrade that was released within 3 months of purchase.  Can you assist or explain if I am missing something?  I would value the upgrade.