btcjson/chainsvrresults.go

@@ -300,6 +300,8 @@ type GetBlockTemplateResult struct {
 	RejectReasion string   `json:"reject-reason,omitempty"`
 
 	ClaimTrieHash string `json:"claimtrie"`
+
+	Rules []string `json:"rules,omitempty"`
 }
 
 // GetMempoolEntryResult models the data returned from the getmempoolentry's

rpcserver.go

@@ -1771,6 +1771,7 @@ func (state *gbtWorkState) blockTemplateResult(useCoinbaseValue bool, submitOld
 	// data, then include the witness commitment in the GBT result.
 	if template.WitnessCommitment != nil {
 		reply.DefaultWitnessCommitment = hex.EncodeToString(template.WitnessCommitment)
+		reply.Rules = append(reply.Rules, "!segwit")
 	}
 
 	if useCoinbaseValue {