RU First or Last?

Hello - quick advise question please!   What's the best approach when upgrading 12c to 19c?   Should I: (1) apply the chosen RU to the 19c home before upgrading, or(2) should I upgrade first and then apply the RU? This is a basic upgrade with the dbupgrade script (nothing fancy).  I presume both would work but I'm unsure what the best practice is (OJVM is required if that makes a difference). Thank you!Charlotte

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