diff --git a/src/Internal/Config/Text.elm b/src/Internal/Config/Text.elm
index 0c0d4ad..c1c2060 100644
--- a/src/Internal/Config/Text.elm
+++ b/src/Internal/Config/Text.elm
@@ -346,6 +346,7 @@ fields :
         }
     , vault :
         { accountData : Desc
+        , nextBatch : Desc
         , rooms : Desc
         , user : Desc
         }
@@ -565,6 +566,9 @@ fields =
         { accountData =
             [ "The account's global private data."
             ]
+        , nextBatch =
+            [ "The next batch that can be used to sync with the Matrix API."
+            ]
         , rooms =
             [ "Directory of joined rooms that the user is a member of."
             ]
diff --git a/src/Internal/Values/Vault.elm b/src/Internal/Values/Vault.elm
index 2725744..1c4112f 100644
--- a/src/Internal/Values/Vault.elm
+++ b/src/Internal/Values/Vault.elm
@@ -44,6 +44,7 @@ import Internal.Values.User as User exposing (User)
 -}
 type alias Vault =
     { accountData : Dict String Json.Value
+    , nextBatch : Maybe String
     , rooms : Hashdict Room
     , user : Maybe User
     }
@@ -56,13 +57,15 @@ type VaultUpdate
     = CreateRoomIfNotExists String
     | MapRoom String Room.RoomUpdate
     | More (List VaultUpdate)
+    | Optional (Maybe VaultUpdate)
     | SetAccountData String Json.Value
+    | SetNextBatch String
     | SetUser User
 
 
 coder : Json.Coder Vault
 coder =
-    Json.object3
+    Json.object4
         { name = Text.docs.vault.name
         , description = Text.docs.vault.description
         , init = Vault
@@ -74,6 +77,13 @@ coder =
             , coder = Json.fastDict Json.value
             }
         )
+        (Json.field.optional.value
+            { fieldName = "nextBatch"
+            , toField = .nextBatch
+            , description = Text.fields.vault.nextBatch
+            , coder = Json.string
+            }
+        )
         (Json.field.required
             { fieldName = "rooms"
             , toField = .rooms
@@ -109,6 +119,7 @@ getAccountData key vault =
 init : Maybe User -> Vault
 init mUser =
     { accountData = Dict.empty
+    , nextBatch = Nothing
     , rooms = Hashdict.empty .roomId
     , user = mUser
     }
@@ -152,8 +163,17 @@ update vu vault =
         More items ->
             List.foldl update vault items
 
+        Optional (Just u) ->
+            update u vault
+
+        Optional Nothing ->
+            vault
+
         SetAccountData key value ->
             setAccountData key value vault
 
+        SetNextBatch nb ->
+            { vault | nextBatch = Just nb }
+
         SetUser user ->
             { vault | user = Just user }
diff --git a/tests/Test/Values/Vault.elm b/tests/Test/Values/Vault.elm
index 3982791..f1c90a0 100644
--- a/tests/Test/Values/Vault.elm
+++ b/tests/Test/Values/Vault.elm
@@ -12,11 +12,12 @@ import Test.Values.User as TestUser
 
 vault : Fuzzer Vault
 vault =
-    Fuzz.map3 Vault
+    Fuzz.map4 Vault
         (Fuzz.string
             |> Fuzz.map (\k -> ( k, Json.encode Json.int 0 ))
             |> Fuzz.list
             |> Fuzz.map Dict.fromList
         )
+        (Fuzz.maybe Fuzz.string)
         (TestHashdict.fuzzer .roomId TestRoom.fuzzer)
         (Fuzz.maybe TestUser.fuzzer)