diff --git a/src/Web/ActivityPub.hs b/src/Web/ActivityPub.hs
index 58cf454..9617f46 100644
--- a/src/Web/ActivityPub.hs
+++ b/src/Web/ActivityPub.hs
@@ -466,7 +466,12 @@ instance (FromJSON a, ToJSON a) => ActivityPub (Collection a) where
         <> "current"    .=? (ObjURI authority <$> curr)
         <> "first"      .=? (PageURI authority <$> firzt)
         <> "last"       .=? (PageURI authority <$> last)
-        <> "items"      .=% items
+        <> itemsProp    .=% items
+        where
+        itemsProp =
+            case typ of
+                CollectionTypeUnordered -> "items"
+                CollectionTypeOrdered -> "orderedItems"
 
 data CollectionPageType
     = CollectionPageTypeUnordered
@@ -527,7 +532,12 @@ instance (FromJSON a, ToJSON a) => ActivityPub (CollectionPage a) where
         <> "prev"       .=? (PageURI authority <$> prev)
         <> "next"       .=? (PageURI authority <$> next)
         <> "startIndex" .=? ind
-        <> "items"      .=% items
+        <> itemsProp    .=% items
+        where
+        itemsProp =
+            case typ of
+                CollectionPageTypeUnordered -> "items"
+                CollectionPageTypeOrdered -> "orderedItems"
 
 data Recipient u = RecipientActor (Actor u) | RecipientCollection (Collection (ObjURI u) u)
 
@@ -1133,7 +1143,7 @@ parsePush :: UriMode u => Authority u -> Object -> Parser (Push u)
 parsePush a o = do
     c <- o .: "object"
     Push
-        <$> (traverse (withAuthorityT a . parseObject) =<< c .: "items")
+        <$> (traverse (withAuthorityT a . parseObject) =<< c .: "items" <|> c .: "orderedItems")
         <*> (traverse (traverse $ withAuthorityT a . parseObject) =<< c .:? "earlyItems")
         <*> c .: "totalItems"
         <*> withAuthorityO a (o .: "target")
@@ -1145,7 +1155,7 @@ encodePush :: UriMode u => Authority u -> Push u -> Series
 encodePush a (Push lateCommits earlyCommits total target context before after)
     =  "object"     `pair` pairs
             (  "type"       .= ("OrderedCollection" :: Text)
-            <> pair "items" (objectList lateCommits)
+            <> pair "orderedItems" (objectList lateCommits)
             <> maybe mempty (pair "earlyItems" . objectList) earlyCommits
             <> "totalItems" .= total
             )