diff --git a/src/TransactionFormats.cpp b/src/TransactionFormats.cpp
index 63283477d..568d076eb 100644
--- a/src/TransactionFormats.cpp
+++ b/src/TransactionFormats.cpp
@@ -20,6 +20,7 @@ TransactionFormat InnerTxnFormats[]=
 		{ S_FIELD(Flags),        STI_UINT32,  SOE_FLAGS,    0 },
 		{ S_FIELD(GeneratorID),  STI_HASH160, SOE_REQUIRED, 0 },
 		{ S_FIELD(Generator),    STI_VL,      SOE_REQUIRED, 0 },
+		{ S_FIELD(SourceTag),    STI_UINT32,  SOE_IFFLAG,   1 },
 		{ S_FIELD(Extensions),   STI_TL,      SOE_IFFLAG,   0x02000000 },
 		{ sfInvalid, NULL,       STI_DONE,    SOE_NEVER,    -1 } }
 	},