https://userapps.support.sap.com/sap/support/knowledge/en/3412565
3412565 - OKEQ | OKEQN | Client xxx has status 'not modifiable | Production | SAP Knowledge Base...
You try to maintain data with transactions OKEQ , OKEQN, S_ALR_87004395 , S_ALR_87004603, or with IMG activity Maintain Plan Versions or Create CO Versions in...
https://history.okeq.org/
OKEQ History Project
historyproject