Generally speaking, as long as the firmware above the version in the matrix, you should be fine. That matrix tells what version things were tested with. Barring any regressions that occur from new features/bug fixes, a more recent version should work fine.
Hence, just pull down the latest SCCP firmware for the phones and see how things fare.
Your issue could be a CME issue instead of a phone firmware issue, though. CME may not be telling the phone the proper softkeys to display when switching states. If you're going to proactively upgrade code, I'd get on a recent rebuild of the CME release, as well.