The actual version is called 3.0.1, but you might have been look finding documentation on its components:
CS : 3.1.1
RME : 4.1.1
CM : 5.0.2
DFM : 3.0.2
IPM : 4.0.1
The upgrade to 3.1 is supported from LMS 3.0 and 3.0.1 and 3.0.1 IDU 20.0 (which includes CM 5.0.3 and DFM 3.0.3).