How To Fix O0021 - Avoid modifications f.applications <> MM/SD (decoupling) -> Devc. &1

O0021 - Overview

• Message type: E = Error

• Message class: O0 - IS-OIL area independent messages

• Message number: 021

• Message text: Avoid modifications f.applications <> MM/SD (decoupling) -> Devc. &1

<ZH>For internal use only</>

What causes this issue?

IS-Oil is based to a large extent on enhancements to the application
components <ZK>Materials Management</> (development class M*) and
<ZK>Sales and Distribution</> (development class V*).
In order to keep our dependence on other components to a minimum, IS-Oil
developers should not develop modifications in "foreign" applications
and minimize the dependencies to other components.
However, in specific cases, it may be necessary to make an enhancement,
but here there are also a couple of logical alternatives:
Check whether or not the enhancement can be solved some other way.
If not, check, if the enhancement can be communicated to the standard
developer, who can then change the coding (if, for example, only
constants can be called in the program, and not oil objects, for example
table definitions). This is to ensure that there are no oil
modifications in the oil coding which are later built into Core coding.
If you are in doubt, call Oil techn.team; the person responsible for the
object can be displayed using Report RDDRESTA or OITRESTA.
First, the correction will have to be built in by us. Sometimes the Core
developers put it into the Hot Package coding, though, before that can
occur. The advantages of this process are obvious:
The object does not have to be maintained and delivered by IS-Oil.
Minimization of transport volume and installation times at customer
site.
Fewer conflicts during the Hot Package merge
Easier to combine IS-Oil with other application components without
having to deal with conflicts or merges.
Standard created the DECO transaction for that, which determines if
sub-objects are being used in objects in a "foreign" environment (in
this case, the OI* dev. classes). In the past the entire SAP system was
delivered, although the customer only ordered/uses a few of the
application components. This solution was developed due to the
dependencies that exist among the modules. Decoupling is used due to the
immense problems brought about by long installation times/upgrade times
as well as delivery postponements, because, for example, one component
was not fully ready in development. That was decided on, because SAP
decided that that situation was unacceptable with respect to the
customers.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

For that reason, the system produces the warning:

How to fix this error?

Within oil development system, please start transaction DECO and verify
the "foreign use" of mentioned above object. Don't hesitate to contact
the oil technical team to discuss a solution to remove the dependency to
an "foreign component".

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message O0021 - Avoid modifications f.applications <> MM/SD (decoupling) -> Devc. &1 ?

  The SAP error message O0021, which states "Avoid modifications f.applications <> MM/SD (decoupling) -> Devc. &1," typically occurs when there are attempts to modify certain application areas that are not allowed due to the decoupling of the MM (Materials Management) and SD (Sales and Distribution) modules. This error is a safeguard to maintain the integrity of the system and prevent unintended consequences from modifications.
  
  Cause:
  
  Decoupling of Modules: The error arises when there is an attempt to make changes in the application that is not permitted due to the decoupling of MM and SD. This is often related to configuration settings or custom developments that are trying to access or modify data in a way that is not supported.
  Custom Development: If there are custom programs, enhancements, or modifications that attempt to change data in a way that violates the rules set by SAP for these modules, this error can occur.
  Incorrect Configuration: Sometimes,