diff --git a/bots/assassin/src/main.rs b/bots/assassin/src/main.rs
index b5d142a..9b0213e 100644
--- a/bots/assassin/src/main.rs
+++ b/bots/assassin/src/main.rs
@@ -118,7 +118,7 @@ fn verify_signature(
 ) -> bool {
     let body_hash = sha2::Sha256::digest(body.as_bytes());
     let body_hash_hex = hex::encode(body_hash);
-    let signing_string = format!("{}.{}.{}.{}", match_id, turn, timestamp, body_hash_hex);
+    let signing_string = format!("{}.{}.{}", match_id, turn, body_hash_hex);
 
     let mut mac = match HmacSha256::new_from_slice(secret.as_bytes()) {
         Ok(m) => m,
diff --git a/bots/farmer/main.go b/bots/farmer/main.go
index 5254e1f..f859213 100644
--- a/bots/farmer/main.go
+++ b/bots/farmer/main.go
@@ -136,7 +136,7 @@ func handleHealth(w http.ResponseWriter, r *http.Request) {
 
 func verifySignature(secret, matchID, turnStr, timestamp string, body []byte, signature string) bool {
 	bodyHash := sha256.Sum256(body)
-	signingString := fmt.Sprintf("%s.%s.%s.%s", matchID, turnStr, timestamp, hex.EncodeToString(bodyHash[:]))
+	signingString := fmt.Sprintf("%s.%s.%s", matchID, turnStr, hex.EncodeToString(bodyHash[:]))
 	mac := hmac.New(sha256.New, []byte(secret))
 	mac.Write([]byte(signingString))
 	expected := hex.EncodeToString(mac.Sum(nil))
diff --git a/bots/guardian/index.php b/bots/guardian/index.php
index fbe7c68..1a84b17 100644
--- a/bots/guardian/index.php
+++ b/bots/guardian/index.php
@@ -136,7 +136,7 @@ function handle_turn($conn, string $secret, GuardianStrategy $strategy, array $h
  */
 function verify_signature(string $secret, string $matchId, string $turn, string $timestamp, string $body, string $signature): bool {
     $bodyHash = hash('sha256', $body);
-    $signingString = "$matchId.$turn.$timestamp.$bodyHash";
+    $signingString = "$matchId.$turn.$bodyHash";
     $expected = hash_hmac('sha256', $signingString, $secret);
     return hash_equals($expected, $signature);
 }
diff --git a/bots/hunter/src/main/java/com/acb/hunter/App.java b/bots/hunter/src/main/java/com/acb/hunter/App.java
index c82c805..524f5ad 100644
--- a/bots/hunter/src/main/java/com/acb/hunter/App.java
+++ b/bots/hunter/src/main/java/com/acb/hunter/App.java
@@ -95,7 +95,7 @@ public class App {
                                            String timestamp, String body, String signature) {
         try {
             String bodyHash = sha256Hex(body);
-            String signingString = matchId + "." + turn + "." + timestamp + "." + bodyHash;
+            String signingString = matchId + "." + turn + "." + bodyHash;
 
             Mac mac = Mac.getInstance("HmacSHA256");
             SecretKeySpec keySpec = new SecretKeySpec(secret.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
diff --git a/bots/opportunist/main.go b/bots/opportunist/main.go
index 9e6f119..3fa2182 100644
--- a/bots/opportunist/main.go
+++ b/bots/opportunist/main.go
@@ -136,7 +136,7 @@ func handleHealth(w http.ResponseWriter, r *http.Request) {
 
 func verifySignature(secret, matchID, turnStr, timestamp string, body []byte, signature string) bool {
 	bodyHash := sha256.Sum256(body)
-	signingString := fmt.Sprintf("%s.%s.%s.%s", matchID, turnStr, timestamp, hex.EncodeToString(bodyHash[:]))
+	signingString := fmt.Sprintf("%s.%s.%s", matchID, turnStr, hex.EncodeToString(bodyHash[:]))
 	mac := hmac.New(sha256.New, []byte(secret))
 	mac.Write([]byte(signingString))
 	expected := hex.EncodeToString(mac.Sum(nil))
diff --git a/bots/phalanx/src/main.rs b/bots/phalanx/src/main.rs
index dd32c91..61ea452 100644
--- a/bots/phalanx/src/main.rs
+++ b/bots/phalanx/src/main.rs
@@ -120,7 +120,7 @@ fn verify_signature(
     let body_hash = sha2::Sha256::digest(body.as_bytes());
     let body_hash_hex = hex::encode(body_hash);
 
-    let signing_string = format!("{}.{}.{}.{}", match_id, turn, timestamp, body_hash_hex);
+    let signing_string = format!("{}.{}.{}", match_id, turn, body_hash_hex);
 
     let mut mac = match HmacSha256::new_from_slice(secret.as_bytes()) {
         Ok(m) => m,
diff --git a/bots/raider/src/main/java/com/acb/raider/App.java b/bots/raider/src/main/java/com/acb/raider/App.java
index 685cd60..1b8d513 100644
--- a/bots/raider/src/main/java/com/acb/raider/App.java
+++ b/bots/raider/src/main/java/com/acb/raider/App.java
@@ -86,7 +86,7 @@ public class App {
                                            String timestamp, String body, String signature) {
         try {
             String bodyHash = sha256Hex(body);
-            String signingString = matchId + "." + turn + "." + timestamp + "." + bodyHash;
+            String signingString = matchId + "." + turn + "." + bodyHash;
 
             Mac mac = Mac.getInstance("HmacSHA256");
             SecretKeySpec keySpec = new SecretKeySpec(secret.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
diff --git a/bots/random/main.py b/bots/random/main.py
index 7325ec7..8354b8f 100644
--- a/bots/random/main.py
+++ b/bots/random/main.py
@@ -68,7 +68,7 @@ class RandomBotHandler(BaseHTTPRequestHandler):
                          timestamp: str, signature: str) -> bool:
         """Verify HMAC signature of incoming request."""
         body_hash = hashlib.sha256(body).hexdigest()
-        signing_string = f"{match_id}.{turn}.{timestamp}.{body_hash}"
+        signing_string = f"{match_id}.{turn}.{body_hash}"
         expected_sig = hmac.new(
             self.secret.encode("utf-8"),
             signing_string.encode("utf-8"),
diff --git a/bots/rusher/src/main.rs b/bots/rusher/src/main.rs
index f8927d2..06d4d44 100644
--- a/bots/rusher/src/main.rs
+++ b/bots/rusher/src/main.rs
@@ -133,7 +133,7 @@ fn verify_signature(
     let body_hash = sha2::Sha256::digest(body.as_bytes());
     let body_hash_hex = hex::encode(body_hash);
 
-    let signing_string = format!("{}.{}.{}.{}", match_id, turn, timestamp, body_hash_hex);
+    let signing_string = format!("{}.{}.{}", match_id, turn, body_hash_hex);
 
     let mut mac = match HmacSha256::new_from_slice(secret.as_bytes()) {
         Ok(m) => m,
diff --git a/bots/scout/main.py b/bots/scout/main.py
index c9b799e..20aa102 100644
--- a/bots/scout/main.py
+++ b/bots/scout/main.py
@@ -330,7 +330,7 @@ class ScoutBotHandler(BaseHTTPRequestHandler):
     def verify_signature(self, body: bytes, match_id: str, turn: str,
                          timestamp: str, signature: str) -> bool:
         body_hash = hashlib.sha256(body).hexdigest()
-        signing_string = f"{match_id}.{turn}.{timestamp}.{body_hash}"
+        signing_string = f"{match_id}.{turn}.{body_hash}"
         expected = hmac.new(
             self.secret.encode("utf-8"),
             signing_string.encode("utf-8"),
diff --git a/bots/swarm/src/index.ts b/bots/swarm/src/index.ts
index 3874bc3..7584639 100644
--- a/bots/swarm/src/index.ts
+++ b/bots/swarm/src/index.ts
@@ -103,7 +103,7 @@ function verifySignature(
   signature: string
 ): boolean {
   const bodyHash = crypto.createHash('sha256').update(body).digest('hex');
-  const signingString = `${matchId}.${turn}.${timestamp}.${bodyHash}`;
+  const signingString = `${matchId}.${turn}.${bodyHash}`;
   const expected = crypto.createHmac('sha256', secret).update(signingString).digest('hex');
   return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
 }