IBM Cloud Pak System 2.3.1.0 was released on Fri 29 November 2019, more details are available at this link about the different release versions. There are a number of significant changes, read all about it here in the IBM Knowledge Center. It is worth noting that IBM has also updated the firmware for a number of components of the hardware stack in this release, as documented here for W3500 models and here for W3550 models. New Compute Nodes now ship with Intel Cascade Lake processors, which require 2.3.1.0 firmware.
A great enhancement in this release is the introduction of custom password policies. IBM PureApplication Platform/System 2.2.6.0 and IBM Cloud Pak System 2.3.0.0 introduced a password policy, however it was not configurable by clients. I explained in this blog post how clients could prepare their patterns for that password policy.
With IBM Cloud Pak System 2.3.1.0, clients can now configure their own custom password policies. The scope for these policies is the Environment Profile, so you could easily setup different policies on the same system. Read about the new password policy here in the Knowledge Center.
IBM Cloud Pak System 