Bluetooth 4.2 is just a software implementation. Therefore it will also support 4.2.

Google_Nexus_7_2012_(asus-grouper).mw

@@ -136,7 +136,7 @@ There is '''multiple hardware revisions''', so this status may not apply to all
 |-
 | Y
 |Bluetooth
-|Works well, it has even BT 4.0, also BT 5.0 headphones works.
+|Works well, it has even BT 4.2, also BT 5.0 headphones works.
 |-
 | Y
 |Sound