diff --git a/django_etesync/serializers.py b/django_etesync/serializers.py
index 37b119e..f0bb1c3 100644
--- a/django_etesync/serializers.py
+++ b/django_etesync/serializers.py
@@ -64,6 +64,7 @@ class CollectionItemRevisionBaseSerializer(serializers.ModelSerializer):
         queryset=models.CollectionItemChunk.objects.all(),
         many=True
     )
+    meta = BinaryBase64Field()
 
     class Meta:
         model = models.CollectionItemRevision