diff --git a/coinbase-exchange.cabal b/coinbase-exchange.cabal
--- a/coinbase-exchange.cabal
+++ b/coinbase-exchange.cabal
@@ -1,5 +1,5 @@
 name:                coinbase-exchange
-version:             0.1.0.0
+version:             0.2.0.0
 synopsis:            Connector library for the coinbase exchange.
 description:         Access library for the coinbase exchange. Allows the use
                      of both the public market data API as well as the private
@@ -28,31 +28,31 @@
 
     other-modules:      Coinbase.Exchange.Rest
 
-    build-depends:      base                ==4.7.*
-                    ,   mtl                 ==2.2.*
-                    ,   resourcet           ==1.1.*
-                    ,   transformers-base   ==0.4.*
-                    ,   conduit             ==1.2.*
-                    ,   conduit-extra       ==1.1.*
-                    ,   http-conduit        ==2.1.*
-                    ,   aeson               ==0.8.*
-                    ,   aeson-casing        ==0.1.*
-                    ,   http-types          ==0.8.*
-                    ,   text                ==1.2.*
-                    ,   bytestring          ==0.10.*
-                    ,   base64-bytestring   ==1.0.*
-                    ,   time                ==1.4.*
-                    ,   scientific          ==0.3.*
-                    ,   uuid                ==1.3.*
-                    ,   uuid-aeson          ==0.1.*
-                    ,   vector              ==0.10.*
-                    ,   hashable            ==1.2.*
-                    ,   deepseq             ==1.3.*
-                    ,   network             ==2.6.*
-                    ,   websockets          ==0.9.*
-                    ,   wuss                ==1.0.*
-                    ,   cryptohash          ==0.11.*
-                    ,   byteable            ==0.1.*
+    build-depends:      base                ==4.*
+                    ,   mtl
+                    ,   resourcet
+                    ,   transformers-base
+                    ,   conduit
+                    ,   conduit-extra
+                    ,   http-conduit
+                    ,   aeson
+                    ,   aeson-casing
+                    ,   http-types
+                    ,   text
+                    ,   bytestring
+                    ,   base64-bytestring
+                    ,   time
+                    ,   scientific
+                    ,   uuid
+                    ,   uuid-aeson
+                    ,   vector
+                    ,   hashable
+                    ,   deepseq
+                    ,   network
+                    ,   websockets
+                    ,   wuss
+                    ,   cryptohash
+                    ,   byteable
 
                     ,   old-locale
 
@@ -61,9 +61,9 @@
     hs-source-dirs:     sbox
     default-language:   Haskell2010
 
-    build-depends:      base                ==4.7.*
-                    ,   http-client         ==0.4.*
-                    ,   http-client-tls     ==0.2.*
+    build-depends:      base                ==4.*
+                    ,   http-client
+                    ,   http-client-tls
 
                     ,   uuid
                     ,   text
@@ -89,11 +89,11 @@
     hs-source-dirs:     test
     default-language:   Haskell2010
 
-    build-depends:      base                ==4.7.*
-                    ,   tasty               ==0.10.*
-                    ,   tasty-th            ==0.1.*
-                    ,   tasty-quickcheck    ==0.8.*
-                    ,   tasty-hunit         ==0.9.*
+    build-depends:      base                ==4.*
+                    ,   tasty
+                    ,   tasty-th
+                    ,   tasty-quickcheck
+                    ,   tasty-hunit
 
                     ,   uuid
                     ,   bytestring
diff --git a/sbox/Main.hs b/sbox/Main.hs
--- a/sbox/Main.hs
+++ b/sbox/Main.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
 
 module Main where
@@ -13,7 +14,6 @@
 import           Network.HTTP.Client.TLS
 import qualified Network.WebSockets              as WS
 import           System.Environment
-import           System.Locale
 
 import           Coinbase.Exchange.MarketData
 import           Coinbase.Exchange.Private
@@ -33,10 +33,10 @@
 btc = "BTC-USD"
 
 start :: Maybe UTCTime
-start = Just $ readTime defaultTimeLocale "%FT%X%z" "2015-04-12T20:22:37+0000"
+start = Just $ parseTimeOrError True defaultTimeLocale "%FT%X%z" "2015-04-12T20:22:37+0000"
 
 end :: Maybe UTCTime
-end = Just $ readTime defaultTimeLocale "%FT%X%z" "2015-04-23T20:22:37+0000"
+end = Just $ parseTimeOrError True defaultTimeLocale "%FT%X%z" "2015-04-23T20:22:37+0000"
 
 accountId :: AccountId
 accountId = AccountId $ fromJust $ fromString "52072cbb-4e76-496f-a479-166cb4d177fa"
diff --git a/src/Coinbase/Exchange/Types/Core.hs b/src/Coinbase/Exchange/Types/Core.hs
--- a/src/Coinbase/Exchange/Types/Core.hs
+++ b/src/Coinbase/Exchange/Types/Core.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP                        #-}
 {-# LANGUAGE DeriveDataTypeable         #-}
 {-# LANGUAGE DeriveGeneric              #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
@@ -24,11 +23,6 @@
 import           Data.UUID.Aeson     ()
 import           Data.Word
 import           GHC.Generics
-#if MIN_VERSION_time(1,5,0)
-import           Data.Time.Format    (dateTimeFmt, defaultTimeLocale)
-#else
-import           System.Locale       (dateTimeFmt, defaultTimeLocale)
-#endif
 
 
 newtype ProductId = ProductId { unProductId :: Text }
@@ -134,7 +128,7 @@
         formatTime defaultTimeLocale coinbaseTimeFormat t ++ "00"
 instance FromJSON CoinbaseTime where
     parseJSON = withText "Coinbase Time" $ \t ->
-        case parseTime defaultTimeLocale coinbaseTimeFormat (T.unpack t ++ "00") of
+        case parseTimeM True defaultTimeLocale coinbaseTimeFormat (T.unpack t ++ "00") of
             Just d -> pure $ CoinbaseTime d
             _      -> fail "could not parse coinbase time format."