SUMMARY
With Strategy 10.6, the Google Maps and ESRI Maps plugin are merged into a single Map plugin that is required to render both, Google Maps as well as ESRI Maps in Strategy Web 10.6. Whereas previously two separate map configuration files were needed to be maintained, only a single configuration file named mapConfig.xml is needed starting with Strategy 10.6.
When upgrading Strategy Web will merge both configuration files. If this process to merge Google Maps and ESRI Maps automatically fails the following error is displayed:

An error has occurred during map plugin migration. Some map functions may not work correctly. Please contact administrator for more information.
<mc> <ec> The content copied from esriConfig.xml in old ESRI plugin. </ec> <gc> The content copied from googleConfig.xml in old Google plugin. </gc> </mc>