Used Openhabian to upgrade from 2.5 to 3.1. Worked really well. Only issue was the Rule page kept saying loading, but didn’t load. Rules were all ngr in Openhab 2.5 .
Had a good look on the forums and ended up looking in /var/lib/openhab/jsondb//automation_rules.json. Eventually spotted that one rule had slightly different order/syntax of some configurations. Changed it and now the Rule page loads.
Incorrect syntax :
"uid": "ce01a778-cafe-40f5-a253-948610da5a15",
"tags": [],
"visibility": "VISIBLE",
"description": "EnableHolidays"
Correct syntax :
"uid": "ce01a778-cafe-40f5-a253-948610da5a15",
"name": "EnableHolidays",
"tags": [],
"visibility": "VISIBLE"
So this worked for me, all of which i got from a collection of other posts :
sudo systemctl stop openhab.service
nano /var/lib/openhab/jsondb//automation_rules.json
sudo openhab-cli clean-cache
sudo systemctl start openhab.service
Many thanks to the developers, especially for OpenHabian :), and to the support on this forum.