diff --git a/log.cabal b/log.cabal
--- a/log.cabal
+++ b/log.cabal
@@ -1,5 +1,5 @@
 name:                log
-version:             0.2.3
+version:             0.2.4
 synopsis:            Structured logging solution with multiple backends
 
 description:         A library that provides a way to record structured log messages with multiple backends.
diff --git a/src/Log/Backend/PostgreSQL.hs b/src/Log/Backend/PostgreSQL.hs
--- a/src/Log/Backend/PostgreSQL.hs
+++ b/src/Log/Backend/PostgreSQL.hs
@@ -106,7 +106,8 @@
       when (T.length newS /= T.length s) $ put True
       return newS
 
-    mapTexts :: forall m. Monad m => (T.Text -> m T.Text) -> LogMessage -> m LogMessage
+    mapTexts :: forall m. (Applicative m, Monad m)
+             => (T.Text -> m T.Text) -> LogMessage -> m LogMessage
     mapTexts doText lm = do
       component <- doText      $ lmComponent lm
       domain    <- mapM doText $ lmDomain lm