diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,9 @@
+# ChangeLog for resourcet
+
+## 1.2.3
+
+* Support `unliftio-core` 0.2.0.0
+
 ## 1.2.2
 
 * Add `MonadFail` instance for `ResourceT`.
diff --git a/Control/Monad/Trans/Resource.hs b/Control/Monad/Trans/Resource.hs
--- a/Control/Monad/Trans/Resource.hs
+++ b/Control/Monad/Trans/Resource.hs
@@ -9,7 +9,7 @@
 {-# LANGUAGE ConstraintKinds #-}
 -- | Allocate resources which are guaranteed to be released.
 --
--- For more information, see <https://www.fpcomplete.com/user/snoyberg/library-documentation/resourcet>.
+-- For more information, see <https://github.com/snoyberg/conduit/tree/master/resourcet#readme>.
 --
 -- One point to note: all register cleanup actions live in the @IO@ monad, not
 -- the main monad. This allows both more efficient code, and for monads to be
diff --git a/Control/Monad/Trans/Resource/Internal.hs b/Control/Monad/Trans/Resource/Internal.hs
--- a/Control/Monad/Trans/Resource/Internal.hs
+++ b/Control/Monad/Trans/Resource/Internal.hs
@@ -254,9 +254,11 @@
 
 -- | @since 1.1.10
 instance MonadUnliftIO m => MonadUnliftIO (ResourceT m) where
-  askUnliftIO = ResourceT $ \r ->
-                withUnliftIO $ \u ->
-                return (UnliftIO (unliftIO u . flip unResourceT r))
+  {-# INLINE withRunInIO #-}
+  withRunInIO inner =
+    ResourceT $ \r ->
+    withRunInIO $ \run ->
+    inner (run . flip unResourceT r)
 
 #define GO(T) instance (MonadResource m) => MonadResource (T m) where liftResourceT = lift . liftResourceT
 #define GOX(X, T) instance (X, MonadResource m) => MonadResource (T m) where liftResourceT = lift . liftResourceT
diff --git a/resourcet.cabal b/resourcet.cabal
--- a/resourcet.cabal
+++ b/resourcet.cabal
@@ -1,5 +1,5 @@
 Name:                resourcet
-Version:             1.2.2
+Version:             1.2.3
 Synopsis:            Deterministic allocation and freeing of scarce resources.
 description:         Hackage documentation generation is not reliable. For up to date documentation, please see: <http://www.stackage.org/package/resourcet>.
 License:             BSD3