Hello Deepak,
Of course there is nothing which is "must", but "highly recommended" . I see that you'll have a lot of changes in terms of OS, DB, SAP Release, EHP level, etc , Executing those operations slowly and with a good plan is the best practice. If you begin with your dev system and if it becomes unoperable, your development activity would stop. Leave at least 2-3 weeks between each changes. The project you're executing is a complex one indeed.
As I understood you'll be executing Step2, OS-DB upgrade at the moment.
I don't know your landscape structure, whether you have QA or not, or just DEV-PROD configuration.
My suggestion is that order:
- If you have not a QA system: (2 SAP Upgrades , 2 system copies)
1a.Copying a sandbox from your ECC5 production.
1b.Upgrading it to ERP6.05.
1c.Upgrading its OS and DB.
1d.Make functional tests on sandbox
1e.Upgrading it to ERP6.07.
1f.Make functional tests on sandbox
2.Same steps for production system
3.Copy upgraded production system onto the dev system.
- If you have a QA system: (3 SAP upgrades, 3 system copies)
1a.Copying a sandbox from your ECC5 production.
1b.Upgrading it to ERP6.05.
1c.Upgrading its OS and DB.
1d.Make functional tests on sandbox
1e.Upgrading it to ERP6.07.
1f.Make functional tests on sandbox
2a.Refreshing your QA with system copy of prod
2b.Upgrade it to ERP6.05
2c.Upgrading its OS and DB.
2d.Make functional tests on QA
2e.Upgrading it to ERP6.07.
2f.Make functional tests on QA
3.Same steps for production system
4.Copy upgraded production system onto the dev system.
I hope this helps,
Serhat