Finally it got published on MyOracle Support (MOS) portal – one of the most helpful notes when we prep for an upgrade or a migration – and potentially the one with the longest title in MOS:
One important note regarding these “Things to Consider” notes:
They will only list issues where either a fix or a proven workaround is available. They don’t list all open issues nor do they recommend every given underscore which may cure one or the other misbehavior.
Just in case you are NOT upgrading/migrating to Oracle Database 18.104.22.168 there are three other helpful notes for earlier releases available as well:
Things to Consider Before Upgrading to 22.214.171.124 to Avoid Poor Performance or Wrong Results
Things to Consider Before Upgrading to 126.96.36.199 to Avoid Poor Performance or Wrong Results
Things to Consider Before Upgrading to 188.8.131.52 to Avoid Poor Performance or Wrong Results