New Recommended Service Levels (RSLs) are available for z/VSE 4.3.1, z/VSE 5.1.2 and z/VSE 5.2.0. The RSL cutoff was December 31, 2014.
RSLs are preventive service offerings. They fill the gap between z/VSE refreshes and HIPER (High Impact or Pervasive APAR) service provided via PSP (Preventive Service Planning) buckets. An RSL consists of a list of all APARs/PTF numbers, that are available at RSL cutoff dates. More information is here .
Have a good weekend.