diff --git a/aztecs-hierarchy.cabal b/aztecs-hierarchy.cabal
--- a/aztecs-hierarchy.cabal
+++ b/aztecs-hierarchy.cabal
@@ -1,18 +1,22 @@
 cabal-version: 2.4
 name:          aztecs-hierarchy
-version:       0.1.0.0
+version:       0.2.0.0
 license:       BSD-3-Clause
 license-file:  LICENSE
 maintainer:    matt@hunzinger.me
 author:        Matt Hunzinger
-synopsis:      A type-safe and friendly Entity-Component-System (ECS) for Haskell
-description:   The Entity-Component-System (ECS) pattern is commonly used in video game develop to represent world objects.
-               .
-               ECS follows the principal of composition over inheritence. Each type of
-               object (e.g. sword, monster, etc), in the game has a unique EntityId. Each
-               entity has various Components associated with it (material, weight, damage, etc).
-               Systems act on entities which have the required Components.
 homepage:      https://github.com/matthunz/aztecs
+synopsis:
+    A type-safe and friendly Entity-Component-System (ECS) for Haskell
+
+description:
+    The Entity-Component-System (ECS) pattern is commonly used in video game develop to represent world objects.
+    .
+    ECS follows the principal of composition over inheritence. Each type of
+    object (e.g. sword, monster, etc), in the game has a unique EntityId. Each
+    entity has various Components associated with it (material, weight, damage, etc).
+    Systems act on entities which have the required Components.
+
 category:      Game Engine
 
 source-repository head
@@ -20,17 +24,16 @@
     location: https://github.com/matthunz/aztecs.git
 
 library
-    exposed-modules:
-        Data.Aztecs.Hierarchy
+    exposed-modules:  Data.Aztecs.Hierarchy
     hs-source-dirs:   src
     default-language: Haskell2010
     ghc-options:      -Wall
     build-depends:
-        base >=4 && <5,
-        aztecs >= 0.3,
-        containers >=0.7,
+        base >=4.6 && <5,
+        aztecs >=0.5,
+        containers >=0.6,
         mtl >=2,
-        linear >= 1
+        linear >=1
 
 test-suite aztecs-hierarchy-test
     type:             exitcode-stdio-1.0
@@ -39,9 +42,9 @@
     default-language: Haskell2010
     ghc-options:      -Wall
     build-depends:
-        base >=4 && <5,
+        base >=4.6 && <5,
         aztecs,
         aztecs-hierarchy,
-        containers >=0.7,
+        containers >=0.6,
         hspec >=2,
         QuickCheck >=2
diff --git a/src/Data/Aztecs/Hierarchy.hs b/src/Data/Aztecs/Hierarchy.hs
--- a/src/Data/Aztecs/Hierarchy.hs
+++ b/src/Data/Aztecs/Hierarchy.hs
@@ -93,7 +93,7 @@
                   then do
                     A.insert entity $ ChildState children
                     let added = Set.difference children childState
-                        removed = Set.difference childState children
+                    -- TODO removed = Set.difference childState children
                     mapM_ (\e -> A.insert e . Parent $ entity) added
                   else return ()
               Nothing -> do
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -7,7 +7,6 @@
 import Data.Aztecs.Hierarchy (Children (..), Parent (..))
 import qualified Data.Aztecs.Hierarchy as Hierarchy
 import qualified Data.Aztecs.Query as Q
-import Data.Aztecs.System (runSystemWithWorld)
 import qualified Data.Aztecs.World as W
 import Data.Functor.Identity (Identity (..))
 import qualified Data.Set as Set
@@ -23,6 +22,6 @@
 prop_addParents = do
   let (_, w) = W.spawnEmpty W.empty
       (e, w') = W.spawn (bundle . Children $ Set.singleton e) w
-  w'' <- runSystemWithWorld Hierarchy.update w'
+  (_, w'') <- runSchedule (schedule Hierarchy.update) w' ()
   let (res, _) = runIdentity $ Q.all Q.fetch w''
   res `shouldMatchList` [Parent e]