We've recently upgraded to 7.1 and I wanted share a 'lesson' learnt from the process with regard to the changes with the CFS config settings.
In 6.1 we had moved some of our CFS settings to use amazon S3 and hence had added <Override xpath ...> settings to our communityserver_override.config file.
I assumed that these would still apply against the new default setting in the 7.x communityserver.config file as documented
<fileStoreGroup name="default" default="true" type="Telligent.Evolution.Extensibility.Storage.Providers.Version1.FileSystemFileStorageProvider, Telligent.Evolution.Components" basePath="~/filestorage/" />
But we found that they were ignored for us. I guess this is because the Override command is looking for a line in the main config file that does not exist any more (as they are all wrapped up in the default group).
Therefore we moved our CFS settings back from the override file to main config file and everything worked fine.