Comment # 3 on bug 1049973 from Sebastian Wagner

> are you sure you ran zypper dup?

yes :)

As ruby2.2 and ruby2.4 have conflicting files, shouldn't the rpms conflict?
Currently it does not:

> zypper if --obsoletes ruby2.4
...
Conflicts      : ruby(abi) = 2.4.0                                

I am now using a new installation (because of other reasons), but I can test
possible solutions on the old one.