Comment # 2 on bug 1122018 from Dominique Leuenberger

A quick debug round shows that the offline upgrade method did not update
libgtkmm2_4-1 to 2.24.5 - which brings this error.

The problem for this is that libgtkmm2_4-1 is not on the DVD, which in turn
makes it not updated.

And since the library does not have versioned symbols, no upgrade is forced for
inkscape (this explains why a zypper dup call does not show this issue, as well
as all clean installs and updates from Leap 15.x)