diff --git a/src/Vervis/API.hs b/src/Vervis/API.hs
index 61d7dcd..e4a64fc 100644
--- a/src/Vervis/API.hs
+++ b/src/Vervis/API.hs
@@ -1187,6 +1187,7 @@ createTicketTrackerC (Entity pidUser personUser) senderActor summary audience tr
                 , activityCapability = Nothing
                 , activitySummary    = summary
                 , activityAudience   = blinded
+                , activityFulfills   = []
                 , activitySpecific   = CreateActivity Create
                     { createObject   = CreateTicketTracker ttdetail (Just (hLocal, ttlocal))
                     , createTarget = Nothing
@@ -1220,11 +1221,12 @@ createTicketTrackerC (Entity pidUser personUser) senderActor summary audience tr
                 , activityCapability = Nothing
                 , activitySummary  = Nothing
                 , activityAudience = Audience recips [] [] [] [] []
+                , activityFulfills =
+                    [encodeRouteHome $ PersonOutboxItemR adminHash obikhidCreate]
                 , activitySpecific = GrantActivity Grant
                     { grantObject   = Left RoleAdmin
                     , grantContext  = encodeRouteHome $ DeckR deckHash
                     , grantTarget   = encodeRouteHome $ PersonR adminHash
-                    , grantFulfills = Just $ encodeRouteHome $ PersonOutboxItemR adminHash obikhidCreate
                     }
                 }
         update obiidGrant [OutboxItemActivity =. persistJSONObjectFromDoc grant]
@@ -1244,6 +1246,7 @@ createTicketTrackerC (Entity pidUser personUser) senderActor summary audience tr
                 , activityCapability = Nothing
                 , activitySummary  = Nothing
                 , activityAudience = AP.Audience recips [] [] [] [] []
+                , activityFulfills = []
                 , activitySpecific = FollowActivity AP.Follow
                     { AP.followObject  = encodeRouteHome $ DeckR deckHash
                     , AP.followContext = Nothing
@@ -1267,6 +1270,7 @@ createTicketTrackerC (Entity pidUser personUser) senderActor summary audience tr
                 , activityCapability = Nothing
                 , activitySummary  = Nothing
                 , activityAudience = Audience recips [] [] [] [] []
+                , activityFulfills = []
                 , activitySpecific = AcceptActivity Accept
                     { acceptObject = ObjURI hLocal luFollow
                     , acceptResult = Nothing
@@ -1400,6 +1404,7 @@ followC (Entity pidSender personSender) summary audience follow@(AP.Follow uObje
                 , activityCapability = Nothing
                 , activitySummary  = summary
                 , activityAudience = blinded
+                , activityFulfills = []
                 , activitySpecific = FollowActivity follow
                 }
         update obiid [OutboxItemActivity =. persistJSONObjectFromDoc doc]
@@ -1428,6 +1433,7 @@ followC (Entity pidSender personSender) summary audience follow@(AP.Follow uObje
                 , activityCapability = Nothing
                 , activitySummary  = Just summary
                 , activityAudience = Audience recips [] [] [] [] []
+                , activityFulfills = []
                 , activitySpecific = AcceptActivity Accept
                     { acceptObject = ObjURI hLocal luFollow
                     , acceptResult = Nothing
diff --git a/src/Vervis/Handler/Person.hs b/src/Vervis/Handler/Person.hs
index 8044612..f60c9c3 100644
--- a/src/Vervis/Handler/Person.hs
+++ b/src/Vervis/Handler/Person.hs
@@ -141,6 +141,8 @@ postPersonOutboxR personHash = do
 
     result <- runExceptT $ do
         verifyAttribution $ AP.activityActor activity
+        unless (null $ AP.activityFulfills activity) $
+            throwE "Specifying 'fulfills' manually isn't allowed currently"
         handle (Entity personID person) actor activity
     case result of
         Left err -> invalidArgs [err]
@@ -160,7 +162,7 @@ postPersonOutboxR personHash = do
             Just (PersonR actorHash) | actorHash == personHash -> return ()
             _ -> throwE "Can't post activity attributed to someone else"
 
-    handle eperson actorDB (AP.Activity _mid _actorAP mcap summary audience specific) =
+    handle eperson actorDB (AP.Activity _mid _actorAP mcap summary audience _fulfills specific) =
         case specific of
             AP.CreateActivity (AP.Create obj mtarget) ->
                 case obj of
diff --git a/src/Vervis/Migration.hs b/src/Vervis/Migration.hs
index b109531..7510620 100644
--- a/src/Vervis/Migration.hs
+++ b/src/Vervis/Migration.hs
@@ -568,6 +568,7 @@ changes hLocal ctx =
                     , activityCapability = Nothing
                     , activitySummary  = Nothing
                     , activityAudience = Audience [] [] [] [] [] []
+                    , activityFulfills = []
                     , activitySpecific = RejectActivity $ Reject fedUri
                     }
             insertEntity $ OutboxItem20190612 pid (persistJSONObjectFromDoc doc) defaultTime
diff --git a/src/Web/ActivityPub.hs b/src/Web/ActivityPub.hs
index 48a2a40..b2bc6f9 100644
--- a/src/Web/ActivityPub.hs
+++ b/src/Web/ActivityPub.hs
@@ -1487,7 +1487,6 @@ data Grant u = Grant
     { grantObject   :: Either Role (ObjURI u)
     , grantContext  :: ObjURI u
     , grantTarget   :: ObjURI u
-    , grantFulfills :: Maybe (ObjURI u)
     }
 
 parseGrant :: UriMode u => Object -> Parser (Grant u)
@@ -1496,14 +1495,12 @@ parseGrant o =
         <$> o .: "object"
         <*> o .: "context"
         <*> o .: "target"
-        <*> o .:? "fulfills"
 
 encodeGrant :: UriMode u => Grant u -> Series
-encodeGrant (Grant obj context target mfulfills)
+encodeGrant (Grant obj context target)
     =  "object"  .= obj
     <> "context" .= context
     <> "target"  .= target
-    <> "fulfills" .=? mfulfills
 
 data OfferObject u = OfferTicket (Ticket u) | OfferDep (TicketDependency u)
 
@@ -1629,6 +1626,7 @@ data Activity u = Activity
     , activityCapability :: Maybe (ObjURI u)
     , activitySummary    :: Maybe TextHtml
     , activityAudience   :: Audience u
+    , activityFulfills   :: [ObjURI u]
     , activitySpecific   :: SpecificActivity u
     }
 
@@ -1643,6 +1641,7 @@ instance ActivityPub Activity where
                 <*> o .:? "capability"
                 <*> (fmap (TextHtml . sanitizeBalance) <$> o .:? "summary")
                 <*> parseAudience o
+                <*> o .:? "fulfills" .!= []
                 <*> do
                     typ <- o .: "type"
                     case typ of
@@ -1660,13 +1659,14 @@ instance ActivityPub Activity where
                         _ ->
                             fail $
                                 "Unrecognized activity type: " ++ T.unpack typ
-    toSeries authority (Activity id_ actor mcap summary audience specific)
+    toSeries authority (Activity id_ actor mcap summary audience fulfills specific)
         =  "type"       .=  activityType specific
         <> "id"         .=? (ObjURI authority <$> id_)
         <> "actor"      .=  ObjURI authority actor
         <> "capability" .=? mcap
         <> "summary"    .=? summary
         <> encodeAudience audience
+        <> "fulfills"   .=% fulfills
         <> encodeSpecific authority actor specific
         where
         activityType :: SpecificActivity u -> Text
@@ -1703,6 +1703,7 @@ emptyActivity = Activity
     , activityCapability = Nothing
     , activitySummary    = Nothing
     , activityAudience   = emptyAudience
+    , activityFulfills   = []
     , activitySpecific   =
         RejectActivity $ Reject $ ObjURI (Authority "" Nothing) topLocalURI
     }