Not my particular area of expertise, however, in the compatibility discussion
The Adabas link (Adalink) routines can be used across versions. For example, Adabas 8 link routines can be used to issue calls to Adabas 7 databases. Unless the new ACBX direct call interface is used, Adabas 7.4 link routines can be used to issue calls to Adabas 8 databases. Software AG recommends that you use the Adabas 8 link routines for all programs that issue Adabas direct calls.
My guess is that if you do not use ACBX, it “might” work.
However, one wonders what would happen if there were an MU with 200 occurrences in a record. If you are not using ACBX, I would hope you would get an error message from Adabas.