diff --git a/snaplet-postgresql-simple.cabal b/snaplet-postgresql-simple.cabal
--- a/snaplet-postgresql-simple.cabal
+++ b/snaplet-postgresql-simple.cabal
@@ -1,5 +1,5 @@
 name:           snaplet-postgresql-simple
-version:        1.0.1.0
+version:        1.0.2.0
 synopsis:       postgresql-simple snaplet for the Snap Framework
 description:    This snaplet contains support for using the Postgresql
                 database with a Snap Framework application via the
@@ -43,7 +43,7 @@
     bytestring                 >= 0.9.1   && < 0.11,
     clientsession              >= 0.7.2   && < 0.10,
     configurator               >= 0.2     && < 0.4,
-    lens                                     < 4.15,
+    lens                       >= 3.7.6   && < 4.16,
     lifted-base                >= 0.2     && < 0.3,
     monad-control              >= 1.0     && < 1.1,
     mtl                        >= 2       && < 2.3,
diff --git a/src/Snap/Snaplet/PostgresqlSimple.hs b/src/Snap/Snaplet/PostgresqlSimple.hs
--- a/src/Snap/Snaplet/PostgresqlSimple.hs
+++ b/src/Snap/Snaplet/PostgresqlSimple.hs
@@ -172,14 +172,16 @@
 --
 -- > d <- nestSnaplet "db" db pgsInit
 -- > count <- liftIO $ runReaderT (execute "INSERT ..." params) d
-instance (MonadIO m, MonadBaseControl IO m) => HasPostgres (ReaderT (Snaplet Postgres) m) where
+instance {-# OVERLAPPING #-} (MonadIO m, MonadBaseControl IO m)
+  => HasPostgres (ReaderT (Snaplet Postgres) m) where
     getPostgresState = asks (^# snapletValue)
     setLocalPostgresState s = local (set snapletValue s)
 
 ------------------------------------------------------------------------------
 -- | A convenience instance to make it easier to use functions written for
 -- this snaplet in non-snaplet contexts.
-instance (MonadIO m, MonadBaseControl IO m) => HasPostgres (ReaderT Postgres m) where
+instance {-# OVERLAPPING #-} (MonadIO m, MonadBaseControl IO m)
+  => HasPostgres (ReaderT Postgres m) where
     getPostgresState = ask
     setLocalPostgresState s = local (const s)
 
diff --git a/src/Snap/Snaplet/PostgresqlSimple/Internal.hs b/src/Snap/Snaplet/PostgresqlSimple/Internal.hs
--- a/src/Snap/Snaplet/PostgresqlSimple/Internal.hs
+++ b/src/Snap/Snaplet/PostgresqlSimple/Internal.hs
@@ -59,7 +59,7 @@
       setLocalPostgresState pg m
 
 
-instance HasPostgres m => HasPostgres (ReaderT r m) where
+instance {-#OVERLAPPABLE #-} HasPostgres m => HasPostgres (ReaderT r m) where
     getPostgresState = lift getPostgresState
     setLocalPostgresState pg (ReaderT m) = ReaderT $ \e ->
       setLocalPostgresState pg (m e)