diff --git a/google-oauth2.cabal b/google-oauth2.cabal
--- a/google-oauth2.cabal
+++ b/google-oauth2.cabal
@@ -1,5 +1,5 @@
 Name:                   google-oauth2
-Version:                0.2.0
+Version:                0.2.1
 Author:                 Pat Brisbin <pbrisbin@gmail.com>
 Maintainer:             Pat Brisbin <pbrisbin@gmail.com>
 License:                MIT
@@ -56,8 +56,8 @@
   GHC-Options:          -Wall
   Exposed-Modules:      Network.Google.OAuth2
   Build-Depends:        base >= 4 && < 5
-                      , HTTP            >= 4000.2       && < 4000.3
-                      , aeson           >= 0.8          && < 0.9
+                      , HTTP            >= 4000.2       && < 4000.4
+                      , aeson           >= 0.8          && < 0.10
                       , bytestring
                       , http-conduit
   Default-Extensions:   OverloadedStrings
diff --git a/src/Network/Google/OAuth2.hs b/src/Network/Google/OAuth2.hs
--- a/src/Network/Google/OAuth2.hs
+++ b/src/Network/Google/OAuth2.hs
@@ -33,8 +33,9 @@
 import Network.HTTP.Conduit
     ( Response(..)
     , httpLbs
+    , newManager
     , parseUrl
-    , withManager
+    , tlsManagerSettings
     , urlEncodedBody
     )
 import Network.HTTP.Base (urlEncode)
@@ -188,7 +189,8 @@
 
     let params' = map (second C8.pack) params
 
-    fmap unsafeDecode $ withManager $ httpLbs $ urlEncodedBody params' request
+    mngr <- newManager tlsManagerSettings
+    unsafeDecode <$> httpLbs (urlEncodedBody params' request) mngr
 
 cachedValue :: Read a => FilePath -> IO (Maybe a)
 cachedValue tokenFile = do