What are the steps that need to be executed or considered in order to upgrade an overlay to a new release:
Execute SYSCLN in the old overlay and process old transactions.
To do so, make a complete copy of the old overlay and rename it.
Copy the old database and rename it.
Set up a new work environment based on the new overlay. Copy all frames into the new work environment (!)
Only the frames of level 5 are mixed; in frames of levels 6 and 8, only compile errors are corrected.
RegisterSettlement, RegisterDocument, Liaall, DiaSav should be mixed with great caution, if at all.
Check in mixed frames.
Search for unused rules using GENTMO and delete them.
It can happen that modules switch levels and as a result occur twice within transactions; you can identify such modules by the 1 at the end. Use a text editor to find and remove such duplicate modules.
Next, perform a Global Compile and post-process any compiling errors.
Using transaction Rxxxxx (example R50600).
Reconcile with SYSUPD code tables and ini files
It can happen that a table, for instance, receives an ETGEXTKEY in a new release. This is why all frames of level 3 must be compared and examined.