diff --git a/qa/rpc-tests/test_framework/mininode.py b/qa/rpc-tests/test_framework/mininode.py
index 5b3ff3b63..93be95c8b 100755
--- a/qa/rpc-tests/test_framework/mininode.py
+++ b/qa/rpc-tests/test_framework/mininode.py
@@ -52,7 +52,7 @@ SPROUT_PROTO_VERSION = 170002  # past bip-31 for ping/pong
 OVERWINTER_PROTO_VERSION = 170003
 SAPLING_PROTO_VERSION = 170006
 BLOSSOM_PROTO_VERSION = 170008
-NU5_PROTO_VERSION = 170050
+NU5_PROTO_VERSION = 170040
 
 MY_SUBVERSION = b"/python-mininode-tester:0.0.3/"
 
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index b31c1faa4..1faec4cee 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -664,7 +664,7 @@ public:
         consensus.vUpgrades[Consensus::UPGRADE_CANOPY].nProtocolVersion = 170012;
         consensus.vUpgrades[Consensus::UPGRADE_CANOPY].nActivationHeight =
             Consensus::NetworkUpgrade::NO_ACTIVATION_HEIGHT;
-        consensus.vUpgrades[Consensus::UPGRADE_NU5].nProtocolVersion = 170050;
+        consensus.vUpgrades[Consensus::UPGRADE_NU5].nProtocolVersion = 170040;
         consensus.vUpgrades[Consensus::UPGRADE_NU5].nActivationHeight =
             Consensus::NetworkUpgrade::NO_ACTIVATION_HEIGHT;
         consensus.vUpgrades[Consensus::UPGRADE_ZFUTURE].nProtocolVersion = 0x7FFFFFFF;
diff --git a/src/version.h b/src/version.h
index 2ebe88c03..2406b89aa 100644
--- a/src/version.h
+++ b/src/version.h
@@ -9,7 +9,7 @@
  * network protocol versioning
  */
 
-static const int PROTOCOL_VERSION = 170015;
+static const int PROTOCOL_VERSION = 170040;
 
 //! initial proto version, to be increased after version/verack negotiation
 static const int INIT_PROTO_VERSION = 209;