This sentence is kinda awkward.  Maybe "This SPI was refactored in Infinispan 6.0.0.Final.  It brings the following improvements over the previous (up to 5.3.x) persistence integration:"

Also in documentation I have written in the past, we usually didn't refer to the version and just document the feature.  Or is that common to for infinispan/jboss?  I am thinking we could just say here are some features provided by the SPI