@reneboer I get it that I can manually delete the files. you said "Never delete from an other places unless you really know what you are doing." This is precisely why this is needed. For someone that purchases a Vera unit and isn't familiar with SSH would be screwed, or would have to contact support every time.
With UI7 coming standard on all new units, and the fact that the plugin list does not clearly state which UI some of the plugins are designed for, people are going to run into this issue. I am new to Vera and I have a linux and a programming background, so I can muddle through a lot of this, but an average user would not be so lucky. I have tested a few plugins now that after installing them it was clear that they had not been tested in UI7, so I ended up deleting them. Being new to Vera, I had initially assumed that uninstalling the plugin would do this, but after looking through the list of luup files after trying and uninstalling a couple, it was clear that it did not.
That brings me to another point, it would be nice if the plugin list made a clear indication of whether it was only for UI5 or had also been tested and was known working in UI7 also. I do realize that some of that would be up to the individual third party plugin developer, but the Vera team could list what plugins were out at the release of a new UI and give developers the option of specifically stating that it is compatible with the newer UI.