diff --git a/app/Main.hs b/app/Main.hs
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -32,7 +32,7 @@
  where
   pgVersion =
     H.Statement "SELECT current_setting('server_version_num')::integer"
-      HE.unit (HD.singleRow $ HD.column HD.int4) False
+      HE.noParams (HD.singleRow $ HD.column $ HD.nonNullable $ HD.int4) False
 
 main :: IO ()
 main = do
diff --git a/postgres-websockets.cabal b/postgres-websockets.cabal
--- a/postgres-websockets.cabal
+++ b/postgres-websockets.cabal
@@ -1,12 +1,12 @@
 name:                postgres-websockets
-version:             0.5.0.1
+version:             0.5.0.2
 synopsis:            Middleware to map LISTEN/NOTIFY messages to Websockets
 description:         Please see README.md
 homepage:            https://github.com/diogob/postgres-websockets#readme
 license:             BSD3
 license-file:        LICENSE
 author:              Diogo Biazus
-maintainer:          diogo@biazus.me
+maintainer:          diogo@biazus.ca
 copyright:           2016 Diogo Biazus
 category:            Web
 build-type:          Simple
@@ -31,13 +31,11 @@
                      , bytestring >= 0.10
                      , postgresql-libpq
                      , lens
-                     , lens-aeson
                      , jose >= 0.6
                      , unordered-containers >= 0.2
                      , postgresql-libpq >= 0.9 && < 1.0
                      , aeson >= 0.11
                      , protolude >= 0.2
-                     , jwt >= 0.7.2 && < 0.8
                      , hasql >= 0.19
                      , either
                      , stm-containers
diff --git a/src/PostgresWebsockets/Broadcast.hs b/src/PostgresWebsockets/Broadcast.hs
--- a/src/PostgresWebsockets/Broadcast.hs
+++ b/src/PostgresWebsockets/Broadcast.hs
@@ -18,7 +18,7 @@
                              ) where
 
 import Protolude
-import qualified STMContainers.Map as M
+import qualified StmContainers.Map as M
 import Control.Concurrent.STM.TChan
 import Control.Concurrent.STM.TQueue
 
diff --git a/src/PostgresWebsockets/Database.hs b/src/PostgresWebsockets/Database.hs
--- a/src/PostgresWebsockets/Database.hs
+++ b/src/PostgresWebsockets/Database.hs
@@ -49,8 +49,8 @@
    where
      mapError :: Either UsageError () -> Either Error ()
      mapError = mapLeft (NotifyError . show)
-     callStatement = HST.Statement ("SELECT pg_notify" <> "($1, $2)") encoder HD.unit False
-     encoder = contramap fst (HE.param HE.text) <> contramap snd (HE.param HE.text)
+     callStatement = HST.Statement ("SELECT pg_notify" <> "($1, $2)") encoder HD.noResult False
+     encoder = contramap fst (HE.param $ HE.nonNullable $ HE.text) <> contramap snd (HE.param $ HE.nonNullable $ HE.text)
 
 -- | Given a Hasql Connection, a channel and a message sends a notify command to the database
 notify :: Connection -> PgIdentifier -> ByteString -> IO (Either Error ())