diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Revision history for supervisors
 
-## 0.1.0.0 -- YYYY-mm-dd
+## 0.2.0.0 -- 2018-12-18
+
+* Make the type of `withSupervisor` more general.
+* Drop unneeded dependency on `unliftio`.
+
+## 0.1.0.0 -- 2018-11-10
 
 * First version. Released on an unsuspecting world.
diff --git a/src/Supervisors.hs b/src/Supervisors.hs
--- a/src/Supervisors.hs
+++ b/src/Supervisors.hs
@@ -19,16 +19,14 @@
     , superviseSTM
     ) where
 
-import UnliftIO.STM
+import Control.Concurrent.STM
 
-import Control.Concurrent
-    (ThreadId, forkIO, myThreadId, threadDelay, throwTo)
+import Control.Concurrent       (ThreadId, forkIO, myThreadId, throwTo)
 import Control.Concurrent.Async (withAsync)
-import Control.Concurrent.STM   (throwSTM)
+import Control.Exception.Safe
+    (Exception, SomeException, bracket, bracket_, toException, withException)
 import Control.Monad            (forever, void)
 import Data.Foldable            (traverse_)
-import UnliftIO.Exception
-    (Exception, SomeException, bracket, bracket_, toException, withException)
 
 import qualified Data.Set as S
 
@@ -60,7 +58,7 @@
 
 -- | Run an IO action with access to a supervisor. Threads spawned using the
 -- supervisor will be killed when the action returns.
-withSupervisor :: (Supervisor -> IO ()) -> IO ()
+withSupervisor :: (Supervisor -> IO a) -> IO a
 withSupervisor f = do
     sup <- newSupervisor
     withAsync (runSupervisor sup) $ const (f sup)
diff --git a/supervisors.cabal b/supervisors.cabal
--- a/supervisors.cabal
+++ b/supervisors.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                supervisors
-version:             0.1.0.0
+version:             0.2.0.0
 stability:           Experimental
 synopsis:            Monitor groups of threads with non-hierarchical lifetimes.
 description:
@@ -39,7 +39,7 @@
 
 common shared-opts
   build-depends:
-      base ^>=4.12
+      base >=4.11 && <4.13
 
 library
   import: shared-opts
@@ -47,8 +47,8 @@
   hs-source-dirs: src/
   build-depends:
       stm ^>=2.5
-    , containers ^>=0.6
-    , unliftio ^>=0.2.8
+    , containers >=0.5.9 && <0.7
+    , safe-exceptions ^>= 0.1.7
     , async ^>=2.2.1
   default-language:    Haskell2010