This is a warning notice, that GeoMedia 2020 Update 2 (release info) is not fully compatible with GeoMedia WebMap 2020 Update 1 (release info).
It had been found that after installing GM 2020 Update 2 the Mobile Publisher command will crash due to changed libraries registrations.
Full compatibility tests were not run, but e.g. WebMap WFS works properly
We do not recommend installing GeoMedia 2020 Update 2 on a server with WebMap 2020 Update 1, unless there's e.g. required a critical fix available in this version, and Mobile Publisher isn't of concern.
WebMap 2020 Update 2 will be the compatible version.