Lol, dont worry, i update my machines frequently, i just dont wanto to update something frequently which holds a significant amount of my wealth as new code can always introduce new problems and i did not noticed any huge security patches in the Trezor firmware updates.
Actually there was,
http://johoe.mooo.com/trezor-power-analysis/ - but the white-hat author contacted SatoshiLabs and the code was fixed in 1.3.3.
Also, there was a not so well-known exploit in 1.3.1 where an adversary who compromised your computer (or the author of your wallet software) could trick you to sign a transaction that sends money to him (you still have to confirm the transaction but the details the TREZOR shows are not correct). This exploit does not work with 1.2.1, but that version has several other weaknesses that have been fixed by now. For example, with 1.2.1 a compromised computer can create a transaction that sends all coins to the miner without requiring a confirmation (but the device has to be unlocked by entering the PIN).