diff --git a/protob/messages-bitcoin.proto b/protob/messages-bitcoin.proto
index 67bd6a73c1..2acab9cd50 100644
--- a/protob/messages-bitcoin.proto
+++ b/protob/messages-bitcoin.proto
@@ -131,6 +131,7 @@ message SignTx {
     optional bool overwintered = 7;                     // only for Zcash
     optional uint32 version_group_id = 8;               // only for Zcash, nVersionGroupId when overwintered is set
     optional uint32 timestamp = 9;                      // only for Capricoin, transaction timestamp
+    optional uint32 branch_id = 10;                     // only for Zcash, BRANCH_ID when overwintered is set
 }
 
 /**
@@ -196,6 +197,7 @@ message TxAck {
         optional bool overwintered = 11;        // only for Zcash
         optional uint32 version_group_id = 12;  // only for Zcash, nVersionGroupId when overwintered is set
         optional uint32 timestamp = 13;         // only for Capricoin, transaction timestamp
+        optional uint32 branch_id = 14;         // only for Zcash, BRANCH_ID when overwintered is set
         /**
         * Structure representing transaction input
         */