When I upgrade IDEA from version 15.1 to 2016 all projects report the following compile time error:
Error:Module '**' production: java.lang.UnsupportedClassVersionError: com/intellij/openapi/vfs/VfsUtil : Unsupported major.minor version 52.0
Env: Mac
osx10.11
jdk7
maven3.3.9
Who knows what the reasons, thanks!