maybe with some interes for some people here trying to debug all the errors they get upgrading to 4.0. I found a command line tool wich i love it so much so i just want to share to others maybe they find it usefull.
https://lnav.org/
in your debian install is as simple as sudo apt install lnav and then to open the logs files just use it like this:
lnav /var/log/openhab/openhab.log /var/log/openhab/events.log
it will highlight errors in red and warnings in yellow by default but it can be customised further if needed
-to move just press e to go down the list trough errors or E to go up the list trough errors same for warning
-by pressing the tab and then i and inputing a specific item name then enter and q and after using the arrow keys will allow to see all entries in the logs
have fun