private void checkOldFallThroughMaps(DBHandle handle, OpenMode openMode, TaskMonitor monitor)
			throws VersionException, CancelledException, IOException {

		if (openMode != OpenMode.UPDATE) {
			return;
		}
		LongPropertyMapDB oldFallThroughs =
			new LongPropertyMapDB(dbHandle, openMode, this, null, addrMap, "FallThroughs", monitor);
		LongPropertyMapDB oldFallFroms =
			new LongPropertyMapDB(dbHandle, openMode, this, null, addrMap, "FallFroms", monitor);
		if (oldFallThroughs.getSize() != 0 || oldFallFroms.getSize() != 0) {
			throw new VersionException(true);
		}
	}
Check for old fall-through/fall-from property maps.  These maps were never fully supported 
so we do not support the read-only mode, however we will support an upgrade of this data 
which is now stored as FALL_THROUGH References.
@param handle handle to database
@param openMode either READ_ONLY, UPDATE, or UPGRADE
@param monitor the task monitor use while upgrading.
@throws VersionException if the database is incompatible with the current schema
@throws IOException if a database io error occurs
@throws CancelledException if the user cancels the upgrade operation
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/code/CodeManager.java