The key to a successful upgrade is to prepare a detailed plan. A detailed plan can prevent problems when upgrading. The plan should include items such as how long it will take to complete a backup and how to verify that the data is complete and secure.

The plan should then be tested, preferably with a copy of the production system data. Testing reveals areas that may cause problems during the upgrade of the production system.

You should then implement the plan, but only after preliminary testing is complete.

The best strategy for upgrading is to first implement any compatibility fixes in the current environment. When the databases and applications are ready, test them in that environment, practice the upgrade, and then perform the upgrade.

Do not use any new features until the upgrade is successfully implemented. Doing so keeps to a minimum the number of variables at each step.