I am using Oracle 19.16RU and JDK 17. Can you recommend which version of ojdbc I should use?
I'm trying ojdbc11 and 23.x.x.x version.
The 23.3 release is a developer release that can be used to test the new features of the 23c database, but should not be used in production as one-off patches won't be delivered in case of bugs. The 23.4 release will be the first production release with full support from Oracle.
Since you're using a 19c database you can also use the 19c JDBC driver. The latest Release Update is 19.21 that can be downloaded here.