IN.MSG.RTN - Use Integration Framework for Interface

I've been seeing a lot of these messages on newer T24 versions when adding a routine to OFS.SOURCE - IN.MSG.RTN or OUT.MSG.RTN.

I need your help guys. From the little materials I have laid my hands on, I do not see how IF exit points replace the functionality of IN and OUT msg routines. I mean, with these two routines we have full access to incoming and outgoing message even before it hits the various versions. So there is a centralized place to do your validations and extra checks - I've seen many sites utilize it in many critical ways.

Hell, even Temenos uses the field for their DS-TELNET OFS source, which is required by the Design Studio for some functionality. So, how are you all working around the restriction?
The dirty way is to JED and add the routine manually after which it is properly triggered. However, this probably wont work with newer versions.

TL;DR:
How exactly can I replace the functionality of OFS Source IN/OUT msg routine using IF? And I'm not talking about version routines.
I will really appreciate any help/pointers.
 

Hi
FYI
we were in the same situation when we upgraded from R13 to R19 back in 2021. The Temenos support advice was: use JED :))) Typical. As we don't use IF, that was it.

Good to know. That settles it. JED for now is the way to go