diff --git a/bookwyrm/activitypub/verbs.py b/bookwyrm/activitypub/verbs.py
index d684171e..900c9a21 100644
--- a/bookwyrm/activitypub/verbs.py
+++ b/bookwyrm/activitypub/verbs.py
@@ -191,6 +191,7 @@ class Like(Verb):
 class Announce(Verb):
     """ boosting a status """
 
+    published: str
     object: str
     type: str = "Announce"
 
diff --git a/bookwyrm/models/status.py b/bookwyrm/models/status.py
index c471a4d9..aa330d61 100644
--- a/bookwyrm/models/status.py
+++ b/bookwyrm/models/status.py
@@ -377,7 +377,7 @@ class Boost(ActivityMixin, Status):
         """ the user field is "actor" here instead of "attributedTo" """
         super().__init__(*args, **kwargs)
 
-        reserve_fields = ["user", "boosted_status"]
+        reserve_fields = ["user", "boosted_status", "published_date"]
         self.simple_fields = [f for f in self.simple_fields if f.name in reserve_fields]
         self.activity_fields = self.simple_fields
         self.many_to_many_fields = []