The general guidance is always use the last LTS release unless there is a specific feature in the non LTS releases that you can’t wait for. So any new development should target 17 at this point.
Unless you want serious long term pain then you shouldn’t be more than one LTS release behind. So if you are not running on JDK 11 or later you should be strongly thinking about upgrading.
Unless you want serious long term pain then you shouldn’t be more than one LTS release behind. So if you are not running on JDK 11 or later you should be strongly thinking about upgrading.