I rebooted this morning and got the Cryaptomator 1.3.4 update notification, which I downloaded and sha256 checked (btw, where can I get the pgp sign file for the release ?!!). So far, so good.
I installed it and it started. Password : ok… Now I have an apparently empty vault… Finally, I had to revert to version 1.3.3. Another minor issue is when you right clic on the notification icon, the options appear empty yet still work (open the app & quit).
Not needing any particular help, I will simply opt out on the upgrade for the moment.