thank you @sihui for your answer.
That’s were I took that from:
openHAB 2.3.0 Build #1232
but how do I know if it is stable, snapshot or whatever else?
Yes, that’s the one in addons folder. It is installed but not active, so it’s not working.
It seems to work:
19 │ Active │ 80 │ 3.12.0.OH │ nrjavaserial
and yet I receive that error:
openhab> bundle:start 277
Error executing command: Error executing command on bundles:
Error starting bundle 277: Could not resolve module: org.openhab.binding.zwave 
Unresolved requirement: Import-Package: org.eclipse.jdt.annotation; resolution:="optional"
Unresolved requirement: Import-Package: org.eclipse.smarthome.config.discovery.usbserial
(I reinstalled so the number changed from 272 to 277).
The zwave binding I had running was installed in habmin, so I went to karaf and uninstalled zwave from there (bundle:uninstall xxx). Then I dropped new binding in the addons folder (to keep the dependencies, as proposed by @chris). It reported installed (but not active) and starting failed with errors as above. I “chown”-ed the binding to openhab:openhab btw, should I not?
Has anybody seen those errors before? Is my only hope to reinstall openhab?
What are those “jdt.annotation” and “smarthome.config.discovery.usbserial” anyway?
All I want is to get the Fibaro Dimmer2 and Qubino Flush Dimmer to report their state. It’s only possible in development binding, isn’t it? (Associations seem not to work well as well ATM, but that’s sth I can live with, or without to be strict.)