*sigh* guys i hate to be the bearer of bad news , but if you are NOT out in the real world then saying MUST is a stretch.
It's strongly ADVISED. There's clear indication that the variable in question is to point to the java release supported, BUT patches for that release do come out and more frequently than CA publishes and sometimes security demands we move the java up a notch to remain compliant.
Which means you do not go beyond the maximum java version the agent can handle but stay within the release level but with suitable patches.
and there endeth the lesson ...
(and trust me i have been out here a lot longer)
Steve C.