The most important part is to update the Oracle client libraries on all the machines running FME, and of course to test everything thoroughly before going into production.
If you're connecting to Esri Geodatabases using Oracle 19c, then you may have to install additional patches from Esri as well, depending on which version you have installed.
You didn't mention which FME version you're running, but if you're far behind the release schedule you might consider this the opportunity for an upgrade as well.
Thank you David. We are using mainly FME version 2020.1 for the moment!
Thank you David. We are using mainly FME version 2020.1 for the moment!
That should work, I have clients using 2018.1 connecting to 19c without any problems.