Upgrading remains a major project for many on premise and legacy applications. It is really quite a pain and this is one reason why I favor Cloud platforms. In the meantime, I hope that I can do upgrading for the last time. These are some tips that the future may not be using for upgrading exercise.
Get the Right Team
The upgrading team is usually a separate team from the support team. This caused a disconnect with miscommunication and the need of knowledge transfer process. There are also instances where upgrading team miss out key components. After all, we suppose the upgrading team to be well versed in the new application. However, the team must involve a right mix of support team to understand the application landscape.
Agile and Systematic
Unfortunately, many upgrading projects follow waterfall model. I favor Agile and systematic approach. In all upgrading project, you need to be systematic in the changes you are doing. You must also be agile to adapt to new options of the upgraded components become a showstopper. Therefore, waterfall model is painfully slower and subjected to delta changes.
As long you are having legacy or on premise application, you will still be having upgrading nightmare. A move to Cloud will cut these costs and time as upgrades are done seamlessly backend. Hopefully, we will not suffer more upgrades in future.