The best practise upgrade process is not clear to me when going from an old APEX release such as 19.1 to the latest release.
Should the process be, upgrade the APEX instance direct from 19.1 to 26.1, test all the apps using the compatibility mode setting as it was in 19.1 then go live and then one app at a time (in a test environment) change the compatibility mode directly from 19.1 to 26.1, then migrate to Prod or should we be doing stages upgrades either at the instance and/or app levels (compatibility mode), eg 19.1 -> 21.2 -> 22.2 -> 23.2 -> 24.2 -> 26.1 while retesting at each step or a combination of the two approaches?
Also, what is safer when performing stages upgrades, aiming for the #.1 or #.2 release and why please?
Thanks.