HTTP PUT command change since OH1? REST Error

Hi guys.
I’m in the process of switching over to OH2 from OH1. I have worked out a lot of the differences and managed to get by with some struggling. But I’m stuck on being able to change/update the state of an item over a HTTP PUT command. What used to work:

no longer works. After searching, I gather this was a function of the old Classic UI, and it seems something like:

should work, but I get a 404 error in the browser and the item state is not changed.

Also when I checkout the openHAB REST API section there is a red error warning at the bottom which upon clicking reads:

{"schemaValidationMessages":[{"level":"error","message":"Can't read from file"}]}

Could this be the reason the http command doesn’t work? What could cause this error and where do I start to rectify it? Any help would be greatly appreciated, thank you in advance.


This might help…

Thankyou very much Farhanito, I must’ve missed this in my searching.