diff --git a/bin/reth/src/test_eth_chain/models.rs b/bin/reth/src/test_eth_chain/models.rs
index 16011d3489..7ba4ef4487 100644
--- a/bin/reth/src/test_eth_chain/models.rs
+++ b/bin/reth/src/test_eth_chain/models.rs
@@ -208,6 +208,9 @@ pub enum ForkSpec {
     /// After Merge plus new PUSH0 opcode
     #[serde(alias = "Merge+3855")]
     MergePush0,
+    /// Fork Spec which is unknown to us
+    #[serde(other)]
+    Unknown,
 }
 
 impl From<ForkSpec> for reth_executor::SpecUpgrades {
@@ -238,6 +241,9 @@ impl From<ForkSpec> for reth_executor::SpecUpgrades {
             ForkSpec::ByzantiumToConstantinopleAt5 | ForkSpec::Constantinople => {
                 panic!("Overridden with PETERSBURG")
             }
+            ForkSpec::Unknown => {
+                panic!("Unknown fork");
+            }
         }
     }
 }
diff --git a/bin/reth/src/test_eth_chain/runner.rs b/bin/reth/src/test_eth_chain/runner.rs
index b7cfa54534..b95c3f3931 100644
--- a/bin/reth/src/test_eth_chain/runner.rs
+++ b/bin/reth/src/test_eth_chain/runner.rs
@@ -91,7 +91,8 @@ pub async fn run_test(path: PathBuf) -> eyre::Result<()> {
                 ForkSpec::MergeEOF |
                 ForkSpec::MergeMeterInitCode |
                 ForkSpec::MergePush0 |
-                ForkSpec::Shanghai,
+                ForkSpec::Shanghai |
+                ForkSpec::Unknown
         ) {
             continue
         }