Solution : https://service.sap.com/sap/support/notes/735696 (SAP Service marketplace login required)
Key words : 
notes include summarized correction instructions, function groups iwo_bapi, software layer almbapi, identical code basis, implement notes manually, alm order bapis, subject area bapi_alm_order_maintain, downgrade kit represent, correction instruction, notes made
Related Notes : 
       
| 738434 | ALMBAPI downgrade: BAPI_ALM_ORDER_MAINTAIN: BAdI for appends | 
| 737337 | Notes for downgrade kit ALMBAPI IV | 
| 736288 | Notes for downgrade kit ALMBAPI III | 
| 736285 | Notes for downgrade kit ALMBAPI II | 
| 736204 | Notes for downgrade kit ALMBAPI I | 
| 735703 | User status is not changeable after technical completion | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |