BRF is obsolete and works in S/4HANA with restrictions

What causes this issue?

The Business Rule Framework (BRF) is obsolete. It has been replaced by
the Business Rule Framework plus (BRFplus).

System Response

In SAP S/4HANA, the functional scope of the BRF is restricted by the
system as follows:
In SAP S/4HANA On Premise Edition, the user is not allowed to create a
new application class. This prevents the BRF from being connected to a
new application.
In SAP S/4HANA Cloud Edition, a maintenance environment is no longer
provided for the BRF.

How to fix this error?

Use the Business Rule Framework plus (BRFplus) instead of the Business
Rule Framework (BRF):
Do not create a new application class in the BRF. Instead, generate a
BRFplus application.
Convert an application that is already using the BRF to the BRFplus.
You must complete this activity before you switch to SAP S/4HANA Cloud
Edition.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.