diff --git a/firestore.rules b/firestore.rules
index f85a5e9b..433b071a 100644
--- a/firestore.rules
+++ b/firestore.rules
@@ -90,7 +90,7 @@ service cloud.firestore {
       return data.keys().hasOnly([
            'userId', 'questionId', 'answerType', 'encryptedPayload',
            'commitmentHash', 'schemaVersion', 'answerKeyReleased',
-           'createdAt', 'updatedAt', 'isRevealed'
+           'answerDate', 'createdAt', 'updatedAt', 'isRevealed'
          ])
         && isSealedPayload(data.encryptedPayload)
         && isCommitmentHash(data.commitmentHash)
@@ -492,7 +492,7 @@ service cloud.firestore {
                 && request.resource.data.keys().hasOnly([
                      'userId', 'questionId', 'answerType', 'writtenText',
                      'selectedOptionIds', 'scaleValue', 'schemaVersion',
-                     'createdAt', 'updatedAt', 'isRevealed'
+                     'answerDate', 'createdAt', 'updatedAt', 'isRevealed'
                    ])
                 && isEncryptedAnswerPayload(request.resource.data))
              );
@@ -512,7 +512,7 @@ service cloud.firestore {
                 && request.resource.data.keys().hasOnly([
                      'userId', 'questionId', 'answerType', 'writtenText',
                      'selectedOptionIds', 'scaleValue', 'schemaVersion',
-                     'createdAt', 'updatedAt', 'isRevealed'
+                     'answerDate', 'createdAt', 'updatedAt', 'isRevealed'
                    ])
                 && isEncryptedAnswerPayload(request.resource.data))
              );