Hello,
I upgraded from OH 3 to 4 and subsequently found out that it would not be so easy.
Where to look for the problem
when I run sudo openhab-config a see:
You don’t have to look anywhere really. You are running on Raspberry Pi OS stretch (Debian 9). That version of the OS reached end of life in 2020. The current version of the Raspberry Pi OS OS is bullseye (Debian 11) and soon will be replaced with bookworm (Debian 12).
You could try to upgrade to buster, and then, to bullseye and I’d give you a 50-75% chance of having a working system after that. But I’d instead recommend taking a backup of everything you need (at a minimum backup your OH configs using openhab-cli. Then with a new SD card burn the openHABian image, let ti configure itself, and restore your backups.
The root problem is OH 4 requires Java 17 which is challenging to install on buster and pretty much impossible on streatch.
OK thank you 