diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,9 +1,15 @@
-## 0.9.0.4 (2018-01-29)
+## 0.9.0.5 (2018-02-05)
 
 Note that this will be the last release in the `0.9` series, excepting
 critical bug fixes or security issues. The next release is expected to
 (slightly) break module export compatibility, but in a way that should
 not affect too many users.
+
+Changes:
+
+  - Support async-2.2.x.
+
+## 0.9.0.4 (2018-01-29)
 
 Changes:
   - The `test-hlint` cabal flag is now disabled by default.
diff --git a/hpio.cabal b/hpio.cabal
--- a/hpio.cabal
+++ b/hpio.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 314c418ac4acf7409780c6803850e71c284df0bb0c42077cb1ad16aa8447a309
+-- hash: 3422bbfd1ca6b82633d357381204ee18fca873f39a41d5b97fb1bdcfe42e5919
 
 name:                   hpio
-version:                0.9.0.4
+version:                0.9.0.5
 synopsis:               Monads for GPIO in Haskell
 description:            This package provides an embedded DSL for writing cross-platform
                         GPIO programs in Haskell. Currently only Linux is supported (via the
@@ -137,7 +137,7 @@
     buildable: False
   else
     build-depends:
-        async >=2.0.2 && <2.2
+        async >=2.0.2 && <2.3
       , base
       , exceptions
       , hpio
@@ -165,7 +165,7 @@
     buildable: False
   else
     build-depends:
-        async >=2.0.2 && <2.2
+        async >=2.0.2 && <2.3
       , base
       , exceptions
       , hpio
@@ -193,7 +193,7 @@
     buildable: False
   else
     build-depends:
-        async >=2.0.2 && <2.2
+        async >=2.0.2 && <2.3
       , base
       , exceptions
       , hpio
diff --git a/package.yaml b/package.yaml
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name:        hpio
-version:     0.9.0.4
+version:     0.9.0.5
 synopsis:    Monads for GPIO in Haskell
 category:    System
 stability:   experimental
@@ -149,7 +149,7 @@
         else:
           dependencies:
           - base
-          - async                >=2.0.2 && <2.2
+          - async                >=2.0.2 && <2.3
           - exceptions
           - hpio
           - mtl