Index: firmware/App/DGCommon.h
===================================================================
diff -u -r0a040a300ce592c2a7cfc095d20f6ddc31036a54 -rfa8082956bc1d94cdd7b2375053a4f35e3159f43
--- firmware/App/DGCommon.h	(.../DGCommon.h)	(revision 0a040a300ce592c2a7cfc095d20f6ddc31036a54)
+++ firmware/App/DGCommon.h	(.../DGCommon.h)	(revision fa8082956bc1d94cdd7b2375053a4f35e3159f43)
@@ -90,6 +90,7 @@
     U08 fpgaMajor;                          ///< DG FPGA major revision
     U08 fpgaMinor;                          ///< DG FPGA minor revision
     U08 fpgaLab;                            ///< DG FPGA lab revision
+    U32 compatibilityRev;                   ///< DG compatibility revision
 } DG_VERSIONS_T;
 #pragma pack(pop)
 
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r4f8187c16dc6eb829b333a29db1161e33fd779b1 -rfa8082956bc1d94cdd7b2375053a4f35e3159f43
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 4f8187c16dc6eb829b333a29db1161e33fd779b1)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision fa8082956bc1d94cdd7b2375053a4f35e3159f43)
@@ -20,6 +20,7 @@
 #include "reg_system.h"
 
 #include "Accel.h"
+#include "Compatible.h"
 #include "ConcentratePumps.h"
 #include "ConductivitySensors.h"
 #include "Fans.h"
@@ -453,6 +454,7 @@
     payload.minor = (U08)DG_VERSION_MINOR;
     payload.micro = (U08)DG_VERSION_MICRO;
     payload.build = (U16)DG_VERSION_BUILD;
+    payload.compatibilityRev = (U32)SW_COMPATIBILITY_REV;
     getFPGAVersions( &payload.fpgaId, &payload.fpgaMajor, &payload.fpgaMinor, &payload.fpgaLab );
 
     // create a message record