Product release is the last stage of the development cycle where 50% of the development team is required to complete the release, support work etc. In this phase, most of the pending works will be non-functional.
Below are a few pending items:
#1 Final Regression by the QA team with Bugfix of the observation.
#2 SIT (System Integration Test) by QA team with Bugfix of the observation.
#3 E2E (End-to-End) testing with Bugfix of the observation.
#4 Security test & make sure no violations of security.
#5 UAT (User Acceptance Test) by Client or internal Client and fix of the observation.
#6 Release document preparation like User Manual, Technical flow document etc.
#7 Pre-production or Staging test before Go-Live.
#8 1-2 months Maintenance or Post-production support.
#9 Scrum Master make sure the final released package is directly from Jenkin or Version control, not from any local shared copy.
#10 RCA (Root Cause Analysis) of any observations during this phase.
If you feel anything else is missing then please help to add.