Tried updating an existing 2.1 instance. Double clicking the setup.exe first returned a message that .Net 4.0 wasn't installed (3.5 SP1 was). Installed .Net 4.0, but now getting a message "Cannot load assembly Microsoft.SharePoint, Version=15.0.0.0. . . Please ensure that the setup.exe for ESRI Maps for SharePoint matches the correct version of SharePoint Server on your machine". This is a dev server with SharePoint Foundation 2010 (v 14.0.6029.1000).
Is there a separate installer for SharePoint 2010 vs 2013?