diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index f033382a63..925041e0cd 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -404,13 +404,23 @@ PX4IO::init()
 	unsigned proto_version = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_PROTOCOL_VERSION);
 	unsigned sw_version = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_SOFTWARE_VERSION);
 
-	if (proto_version != PX4IO_P_CONFIG_PROTOCOL_VERSION) {
+	if (proto_version != PX4IO_P_CONFIG_PROTOCOL_VERSION_MAGIC) {
 		mavlink_log_emergency(_mavlink_fd, "[IO] ERROR! PROTO VER MISMATCH: v%u vs v%u\n",
 			proto_version,
-			PX4IO_P_CONFIG_PROTOCOL_VERSION);
+			PX4IO_P_CONFIG_PROTOCOL_VERSION_MAGIC);
 
 		mavlink_log_emergency(_mavlink_fd, "[IO] Please update PX4IO firmware.");
-		log("protocol version mismatch (v%u on IO vs v%u on FMU)", proto_version, PX4IO_P_CONFIG_PROTOCOL_VERSION);
+		log("protocol version mismatch (v%u on IO vs v%u on FMU)", proto_version, PX4IO_P_CONFIG_PROTOCOL_VERSION_MAGIC);
+		return 1;
+	}
+
+	if (sw_version != PX4IO_P_CONFIG_SOFTWARE_VERSION_MAGIC) {
+		mavlink_log_emergency(_mavlink_fd, "[IO] ERROR! SOFTWARE VER MISMATCH: v%u vs v%u\n",
+			proto_version,
+			PX4IO_P_CONFIG_SOFTWARE_VERSION_MAGIC);
+
+		mavlink_log_emergency(_mavlink_fd, "[IO] Please update PX4IO firmware.");
+		log("software version mismatch (v%u on IO vs v%u on FMU)", sw_version, PX4IO_P_CONFIG_SOFTWARE_VERSION_MAGIC);
 		return 1;
 	}
 
diff --git a/src/modules/px4iofirmware/protocol.h b/src/modules/px4iofirmware/protocol.h
index 497e6af8e2..6c6c7b4e27 100644
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@@ -75,10 +75,13 @@
 #define REG_TO_FLOAT(_reg)	((float)REG_TO_SIGNED(_reg) / 10000.0f)
 #define FLOAT_TO_REG(_float)	SIGNED_TO_REG((int16_t)((_float) * 10000.0f))
 
+#define PX4IO_P_CONFIG_PROTOCOL_VERSION_MAGIC	2
+#define PX4IO_P_CONFIG_SOFTWARE_VERSION_MAGIC	2
+
 /* static configuration page */
 #define PX4IO_PAGE_CONFIG		0
-#define PX4IO_P_CONFIG_PROTOCOL_VERSION		2	/* magic numbers TBD */
-#define PX4IO_P_CONFIG_SOFTWARE_VERSION		1	/* magic numbers TBD */
+#define PX4IO_P_CONFIG_PROTOCOL_VERSION		0	/* magic numbers */
+#define PX4IO_P_CONFIG_SOFTWARE_VERSION		1	/* magic numbers */
 #define PX4IO_P_CONFIG_BOOTLOADER_VERSION	2	/* get this how? */
 #define PX4IO_P_CONFIG_MAX_TRANSFER		3	/* maximum I2C transfer size */
 #define PX4IO_P_CONFIG_CONTROL_COUNT		4	/* hardcoded max control count supported */
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index a092fc93b5..148514455a 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -57,8 +57,8 @@ static void	pwm_configure_rates(uint16_t map, uint16_t defaultrate, uint16_t alt
  * Static configuration parameters.
  */
 static const uint16_t	r_page_config[] = {
-	[PX4IO_P_CONFIG_PROTOCOL_VERSION]	= 1,	/* XXX hardcoded magic number */
-	[PX4IO_P_CONFIG_SOFTWARE_VERSION]	= 1,	/* XXX hardcoded magic number */
+	[PX4IO_P_CONFIG_PROTOCOL_VERSION]	= PX4IO_P_CONFIG_PROTOCOL_VERSION_MAGIC,
+	[PX4IO_P_CONFIG_SOFTWARE_VERSION]	= PX4IO_P_CONFIG_SOFTWARE_VERSION_MAGIC,
 	[PX4IO_P_CONFIG_BOOTLOADER_VERSION]	= 3,	/* XXX hardcoded magic number */
 	[PX4IO_P_CONFIG_MAX_TRANSFER]		= 64,	/* XXX hardcoded magic number */
 	[PX4IO_P_CONFIG_CONTROL_COUNT]		= PX4IO_CONTROL_CHANNELS,