Simple as that -- How is an install upgrade performed? Links, anyone?
1 Answer
If you're upgrading EE3 to another version of EE3: https://docs.expressionengine.com/latest/installation/update.html
If you're upgrading from EE2 to EE3: https://docs.expressionengine.com/latest/installation/upgrade_from_2.x.html
If you're upgrading EE2 to EE2: https://docs.expressionengine.com/v2/installation/update.html