diff --git a/quiche/blind_sign_auth/proto/spend_token_data.proto b/quiche/blind_sign_auth/proto/spend_token_data.proto
index 29cf891..671067b 100644
--- a/quiche/blind_sign_auth/proto/spend_token_data.proto
+++ b/quiche/blind_sign_auth/proto/spend_token_data.proto
@@ -12,37 +12,29 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-edition = "2023";
+syntax = "proto3";
 
 package privacy.ppn;
 
 import "quiche/blind_sign_auth/proto/public_metadata.proto";
 import "anonymous_tokens/proto/anonymous_tokens.proto";
 
-option features.field_presence = IMPLICIT;
-
 message SpendTokenData {
   // Public metadata associated with the token being spent.
   // See go/ppn-token-spend and go/ppn-phosphor-at-service for details.
   PublicMetadata public_metadata = 1;
-
   // The unblinded token to be spent which was blind-signed by Phosphor.
   bytes unblinded_token = 2;
-
   // The signature for the token to be spent, obtained from Phosphor and
   // unblinded.
   bytes unblinded_token_signature = 3;
-
   // The version number of the signing key that was used during blind-signing.
   uint64 signing_key_version = 4;
-
   // A use case identifying the caller. Should be a fixed, hardcoded value to
   // prevent cross-spending tokens.
   anonymous_tokens.AnonymousTokensUseCase use_case = 5;
-
   // Nonce used to mask plaintext message before cryptographic verification.
   bytes message_mask = 6;
-
   // General public metadata. Use deserializer to inspect. Only set one of this
   // or public_metadata.
   bytes binary_public_metadata = 7;
@@ -51,10 +43,8 @@
 message PrivacyPassTokenData {
   // The base64 encoded Privacy Pass token.
   string token = 1;
-
   // The base64 encoded, Privacy Pass compliant binary public metadata.
   string encoded_extensions = 2;
-
   // Populate only for testing, this will affect which public key is used.
   anonymous_tokens.AnonymousTokensUseCase use_case_override =
       3;