Keeping systems current is critical for many reasons, including features and functionality improvements. Planning and communication are key to successful upgrades. Most organizations have a test environment or sandbox. The best practice is to copy most current data from your live environment to your sandbox.
Next, be sure to read the release notes. Take down the current release to your sandbox environment only. Be sure to upgrade all linked products as some are dependent on each other. Based on the release notes to know which areas have been upgraded, perform normal routines in the sandbox and test for functionality.
Give a time frame to the end-users for their testing. For example, allow two weeks for testing and have a person in AP perform normal tasks such as entering and invoice and cutting a check. Once testing and acceptance is complete, you are ready to upgrade your live environment. Plan your timing, inform the staff, distribute the release notes, upgrade. Voila!
If you need help with this, the Cornerstone team has decades of experience helping people through this. We even perform the normal testing for some of our clients as their staff may be too busy to test.