I was following this manual

Put the version number on your EPDM datacard - 3DVision Blog

to assign the "Version" of EPDM to a variable with the same name. However, this idea has one problem:

Case 1: say there is a part with the version  10. The drawing shows this version in a note linked to custom property. If a part is checked in, just before the actual checkin the value is changed to version 11. So the drawing is updated and everything is OK.

Case 2: say now I have a version 11 of that file. I renew the drawing, and the note still shows version 11 of that part. I now check in the part file, and also the drawing as a reference. In this case, the part custom property is updated to be version 12. But the drawing went to the vault as it was, without changing that note to show "Version 12".

Therefore, I want to change the dispatch action into changing the variable at the check out instead of check in (I know that drawings will show the future version number until the part file is checked in, but that's ok).

I changed these options, but the variable is not updated, I can not find out why. These are the settings:

The message box "Hello" appears as it should during check out. But the variable is not changed.

EDIT: I have also tried to use a simple equation:

Add(2,3)

It is not working at check out. I have no idea why ...

These are options for a variable:

Everything is working correctly according to the manual - if the variable is changed during check in, so the settings of the variable are fine. But in my case I want the variable to be changed at check out, and it is not working. The message box is shown, which shows that the trigger is working, but not the change of the variable. Would you please help me clarify what am I doing wrong?

Thank you for your advice