diff --git a/hasql-postgres.cabal b/hasql-postgres.cabal
--- a/hasql-postgres.cabal
+++ b/hasql-postgres.cabal
@@ -1,7 +1,7 @@
 name:
   hasql-postgres
 version:
-  0.7.2
+  0.7.3
 synopsis:
   A "PostgreSQL" backend for the "hasql" library
 description:
@@ -82,7 +82,7 @@
     uuid == 1.3.*,
     vector == 0.10.*,
     time >= 1.4 && < 1.6,
-    hashtables == 1.1.*,
+    hashtables >= 1.1 && < 1.3,
     scientific >= 0.2 && < 0.4,
     text >= 1 && < 1.3,
     bytestring >= 0.10 && < 0.11,
@@ -128,14 +128,14 @@
     -- parsers:
     attoparsec >= 0.10 && < 0.13,
     -- database:
-    hasql == 0.2.*,
+    hasql == 0.4.*,
     postgresql-binary == 0.5.*,
     postgresql-libpq == 0.9.*,
     -- data:
     uuid == 1.3.*,
     vector == 0.10.*,
     time >= 1.4 && < 1.6,
-    hashtables == 1.1.*,
+    hashtables >= 1.1 && < 1.3,
     scientific >= 0.2 && < 0.4,
     text >= 1 && < 1.3,
     bytestring >= 0.10 && < 0.11,
@@ -171,7 +171,7 @@
   build-depends:
     hasql-postgres,
     hasql-backend,
-    hasql == 0.2.*,
+    hasql == 0.4.*,
     -- testing:
     HTF == 0.12.*,
     quickcheck-instances == 0.3.*,
@@ -216,7 +216,7 @@
     postgresql-simple == 0.4.*,
     hasql-postgres,
     hasql-backend,
-    hasql == 0.2.*,
+    hasql == 0.4.*,
     -- random:
     QuickCheck == 2.7.*,
     quickcheck-instances == 0.3.*,
diff --git a/tests/Main.hs b/tests/Main.hs
--- a/tests/Main.hs
+++ b/tests/Main.hs
@@ -35,6 +35,18 @@
   htfMain $ htf_thisModulesTests
 
 
+test_wrongPort =
+  let 
+    backendSettings = H.Postgres "localhost" 1 "postgres" "" "postgres"
+    poolSettings = fromJust $ sessionSettings 6 30
+    io =
+      H.session backendSettings poolSettings $ do
+        H.tx Nothing $ H.unit [H.q|DROP TABLE IF EXISTS a|]
+    in 
+      assertThrowsIO io $ \case
+        H.CantConnect _ -> True
+        _ -> False
+
 test_sameStatementUsedOnDifferentTypes =
   session1 $ do
     liftIO . assertEqual (Just (Identity ("abc" :: Text))) =<< do 
@@ -77,28 +89,6 @@
       id2 <- (fmap . fmap) runIdentity $ single $ [q|INSERT INTO a (v) VALUES (2) RETURNING id|]
       return (id1, id2)
 
-test_transactionConflictResolution =
-  do
-    session1 $ tx Nothing $ do
-      unit [q|DROP TABLE IF EXISTS a|]
-      unit [q|CREATE TABLE a ("id" int8, "v" int8, PRIMARY KEY ("id"))|]
-      unit [q|INSERT INTO a (id, v) VALUES ('7', '0')|]
-    semaphore <- SSem.new (-1)
-    SlaveThread.fork $ session >> SSem.signal semaphore
-    SlaveThread.fork $ session >> SSem.signal semaphore
-    SSem.wait semaphore
-    r <- session1 $ tx Nothing $ single [q|SELECT v FROM a WHERE id='7'|]
-    assertEqual (Just (Identity (200 :: Int))) r
-  where
-    session =
-      session1 $ do
-        replicateM 100 $ tx (Just (Serializable, True)) $ do
-          Just (Identity (v :: Int)) <- single [q|SELECT v FROM a WHERE id='7'|]
-          unit $ [q|UPDATE a SET v=? WHERE id='7'|] (succ v)
-
-test_transaction =
-  unitTestPending ""
-
 test_cursorResultsOrder =
   session1 $ do
     r :: [Word] <-
@@ -213,17 +203,17 @@
 
 selectSelf :: 
   Backend.Mapping Postgres a => 
-  a -> Session Postgres IO (Maybe a)
+  a -> Session Postgres s IO (Maybe a)
 selectSelf v =
   tx Nothing $ (fmap . fmap) runIdentity $ single $ [q| SELECT ? |] v
 
 validMappingSession :: 
   Backend.Mapping Postgres a => Typeable a => Show a => Eq a => 
-  a -> Session Postgres IO ()
+  a -> Session Postgres s IO ()
 validMappingSession v =
   selectSelf v >>= liftIO . assertEqual (Just v)
 
-session1 :: Session Postgres IO r -> IO r
+session1 :: (forall s. Session Postgres s IO r) -> IO r
 session1 =
   session backendSettings poolSettings
   where