diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## [Unreleased]
 
+## [0.1.2]
+### Changed
+- apecs version bump
+
 ## [0.1.0]
 ### Added
 - Split out the STM parts of the main apecs package
diff --git a/apecs-stm.cabal b/apecs-stm.cabal
--- a/apecs-stm.cabal
+++ b/apecs-stm.cabal
@@ -1,5 +1,5 @@
 name:                apecs-stm
-version:             0.1.1
+version:             0.1.2
 homepage:            https://github.com/jonascarpay/apecs-stm#readme
 license:             BSD3
 license-file:        LICENSE
@@ -28,13 +28,13 @@
   default-language:
     Haskell2010
   build-depends:
-    base >= 4.7 && < 5,
-    containers,
-    stm,
-    list-t,
-    vector,
-    template-haskell,
-    stm-containers,
-    apecs >= 0.7
+    apecs            >= 0.7  && < 0.9,
+    base             >= 4.9  && < 5,
+    containers       >= 0.5  && < 0.8,
+    list-t           >= 1    && < 1.2,
+    stm              >= 2.3  && < 3,
+    stm-containers   >= 1.1  && < 2,
+    template-haskell >= 2.12 && < 3,
+    vector           >= 0.10 && < 0.13
   ghc-options:
     -Wall
diff --git a/src/Apecs/STM.hs b/src/Apecs/STM.hs
--- a/src/Apecs/STM.hs
+++ b/src/Apecs/STM.hs
@@ -48,9 +48,11 @@
   explInit = Map <$> M.new
 instance ExplGet STM (Map c) where
   {-# INLINE explExists #-}
-  explExists (Map m) ety = isJust   <$> M.lookup ety m
   {-# INLINE explGet #-}
-  explGet    (Map m) ety = fromJust <$> M.lookup ety m
+  explExists (Map m) ety = isJust   <$> M.lookup ety m
+  explGet    (Map m) ety = flip fmap (M.lookup ety m) $ \case
+    Just c -> c
+    Nothing -> error $ "Reading non-existant STM Map component for entity " <> show ety
 instance ExplSet STM (Map c) where
   {-# INLINE explSet #-}
   explSet (Map m) ety x = M.insert x ety m
@@ -66,8 +68,8 @@
   explInit = S.atomically explInit
 instance ExplGet IO (Map c) where
   {-# INLINE explExists #-}
-  explExists m e = S.atomically $ explExists m e
   {-# INLINE explGet #-}
+  explExists m e = S.atomically $ explExists m e
   explGet m e = S.atomically $ explGet m e
 instance ExplSet IO (Map c) where
   {-# INLINE explSet #-}
@@ -87,8 +89,8 @@
 instance ExplGet STM (Unique c) where
   {-# INLINE explGet #-}
   explGet (Unique ref) _ = flip fmap (readTVar ref) $ \case
-    Nothing -> error "Reading empty Unique"
     Just (_, c)  -> c
+    Nothing -> error $ "Reading non-existant Unique component"
   {-# INLINE explExists #-}
   explExists (Unique ref) ety = maybe False ((==ety) . fst) <$> readTVar ref