Hi Sajid ,
You have posted SBX was upgraded . Was it a copy of the Production system ( recent copy ) . If it was a recent production copy you need to track the SPAU/SPDD as this is sure to appear in production .
In our case we did the upgrade in 3 months ( moved through SBX ,DEV , QAS , PRE- PROD and prod - didnt have a parallel landscape ) but was not constrained by on going activity .
Best option for you is to do a restore to DEV1 ( from DEV ) and start the work on SPAU , SPDD ( of SBX here ) and continue the work from here . Those changes which can be ok to move to PROD by the time you upgrade your PRE-PROD system can go through , the rest have to wait until the upgrade is complete on PROD .
We completely freezed the changes by the time the upgrade reached our pre-prod system . The last one month we had to wait . No new transports were allowed into the upgraded preprod ( other than the SPAU/SPDD and other upgade related fixes ) .
The idea around these at this point is to make sure that the pre- prod ( may be in ur case QAS ) upgrade is as close to the production upgrade. Here other projects have to wait as the importance was given to business continuity .
In your case you should plan in such a way that the business at no cost is affected even if other pjts have to wait or work needs to be re-done.
Thanks ,
Manu