The version you are using still uses the Dojo based Client API. I know Mendix is working on a pluggable version of this widget, see:
So, I guess in the near future the Maps widget will be replaced with this one.
Until that time, forget about those deprecated warnings, or update the widget yourself. This update to remove those warnings is very easy. In the Client API documentation it is described how to rewrite from mx.ui.action to mx.data.action:
thanks for the prompt answer.
I already updated the Maps widget with the mx.data.action and just found that the deprecation warning is related to the MindSphere TimeSeries Widget (which is used after clicking on a marker in the map). This widget uses the deprecated method at the moment.