Q: javac -source and -target version

Hi,

 Some of Java packages are FTBFS with Java21 due to javac -source and -target
 version is lower than that is supported in Java21.

 Well, is there any text / document to use which version should be
 used for -source and -target version, or is just dropgping those options
 allowed?


 Maybe I asked it before but cannot remember the reasons...
 so I hope someone let me know it.


 Thanks!