Can anybody confirm this (so is a upgrade
recommended?)
I can't confirm that since I have used TDE only from pre-v14.0.0 (Dec 2012) but I
would say there is no reason to not use 3.5.13.2.
That has several bug fixes compared to 3.5.13.
Unless you have strong points against that, I would recommend you update to 3.5.13.2.
Cheers
Michele