diff --git a/networks/genesis/union-testnet-9/genesis.json b/networks/genesis/union-testnet-9/genesis.json
index bfbb7d873d..aa4e577bee 100644
--- a/networks/genesis/union-testnet-9/genesis.json
+++ b/networks/genesis/union-testnet-9/genesis.json
@@ -1948,8 +1948,8 @@
       },
       "feature": {
         "vote_extensions_enable_height": "0",
-        "pbts_enable_height": "0"
+        "pbts_enable_height": "1"
       }
     }
   }
-}
\ No newline at end of file
+}