Hello Babynus,
Here is results from somes tests I've made yesterday and this morning.
I've tested the upgrade from a clean environnement (Projeqtor in version 5.3.3 with a few data) to the version 5.5.4.
It's ok : I can creat a note, a project, without error warning or problem.
But when I import in this "clean environnement" a dump from my "production Database" (which is in 5.5.4 too), I found again my problem :
1) I can't create a project or an activity, I've got this message
2) I can create a new note but it's appear with an #0 id and no text , and can't be erase, with this error message :
3) I can create a ticket
It's a "weird" behavion

and I don't understand what's happened : is my production database corrupted ? How can see that and fix that ?
It's really problematic today : I can't use my "production environnement" anymore : there ar to many errors

.
Another questions :
* what's happend if I restore on a 5.5.3 (or before) environnement a database from a 5.5.4 environnement : is it possible ?
* what's happend if I restore on a 5.5.4 environnement a database from a 5.5.3 environnement (or before): is it possible ?
Thanks for your help, I'm in a very difficult situation today
regards,
Damien