SAP Upgrade of an ABAP Stack - SAP Basis Administration - page 482

F IGURE 25-1 Upgrade software logistics
The key steps of the upgrade in a five-System-Landscape are explained here. Refer to
Figure 25-1 as you follow the steps.
1. The development system (DEV) is copied to a production support system (PSS).
2. The quality assurance (QAS) system is copied to a production support QA system
(PSQ).
3. A transport path is set up between PSS and PSQ.
4. A transport path is set up between PSQ and the production system (PRD).
5. The DEV is upgraded to the target release.
6. Production support transports are backfilled to DEV from PSS.
7. The QAS system is refreshed from PRD (database copy from PRD).