diff --git a/src/main/java/com/mercadopago/webhook/WebhookSignatureValidator.java b/src/main/java/com/mercadopago/webhook/WebhookSignatureValidator.java
index 9dd1e996..82c36306 100644
--- a/src/main/java/com/mercadopago/webhook/WebhookSignatureValidator.java
+++ b/src/main/java/com/mercadopago/webhook/WebhookSignatureValidator.java
@@ -53,7 +53,7 @@ private WebhookSignatureValidator() {
    *                   manifest before computing the HMAC
    * @param dataId     value of the {@code data.id} query parameter; may be {@code null} or
    *                   blank, in which case the {@code id:} pair is omitted. When present,
-   *                   it is lowercased before being included in the manifest
+   *                   it is included in the manifest exactly as received
    * @param secret     secret signature configured for the application in Tus Integraciones,
    *                   used as the HMAC key
    * @throws MPInvalidWebhookSignatureException when the signature is missing, malformed, or
@@ -201,7 +201,7 @@ private static ParsedSignature parseSignatureHeader(String header) {
   private static String buildManifest(String dataId, String requestId, String timestamp) {
     StringBuilder sb = new StringBuilder();
     if (dataId != null) {
-      sb.append("id:").append(dataId.toLowerCase()).append(';');
+      sb.append("id:").append(dataId).append(';');
     }
     if (requestId != null) {
       sb.append("request-id:").append(requestId).append(';');
diff --git a/src/test/java/com/mercadopago/webhook/WebhookSignatureValidatorTest.java b/src/test/java/com/mercadopago/webhook/WebhookSignatureValidatorTest.java
index 79cac0e8..2f622af1 100644
--- a/src/test/java/com/mercadopago/webhook/WebhookSignatureValidatorTest.java
+++ b/src/test/java/com/mercadopago/webhook/WebhookSignatureValidatorTest.java
@@ -27,7 +27,7 @@ private static String computeHash(String dataId, String requestId, String ts, St
     try {
       StringBuilder mb = new StringBuilder();
       if (dataId != null && !dataId.isEmpty()) {
-        mb.append("id:").append(dataId.toLowerCase()).append(';');
+        mb.append("id:").append(dataId).append(';');
       }
       if (requestId != null && !requestId.isEmpty()) {
         mb.append("request-id:").append(requestId).append(';');
@@ -68,9 +68,10 @@ void happyPathLowercase() {
 
   // case 2
   @Test
-  void uppercaseDataIdIsLowercased() {
+  void uppercaseDataIdIsPreserved() {
+    String upperHash = computeHash(DATA_ID_RAW, REQUEST_ID, TS, SECRET);
     assertDoesNotThrow(() ->
-        WebhookSignatureValidator.validate(buildHeader(validHash()), REQUEST_ID, DATA_ID_RAW, SECRET));
+        WebhookSignatureValidator.validate(buildHeader(upperHash), REQUEST_ID, DATA_ID_RAW, SECRET));
   }
 
   // case 3