diff --git a/package.dhall b/package.dhall
index 7868e83..847c418 100644
--- a/package.dhall
+++ b/package.dhall
@@ -1,10 +1,10 @@
 { Schema =
       ./schema.dhall
-        sha256:99dc461563042c4c4df92a8ce5a66842496be9fb2303bd0d7bf344417888cf61
+        sha256:1aa8c2f42fc6fc3055a35c1285314340f934aa50226c6cdc96f8d19471a84835
     ? ./schema.dhall
 , Schema/validate =
       ./validate.dhall
-        sha256:03d846ce0f42478c630708dd45cb9883f74f6ad97d4c0325bd6f6879368c7bd1
+        sha256:78f05c1c7d49d3d8854b8a000600a30e55c7c2771bf9f91dc4717ef30a191a91
     ? ./validate.dhall
 , Schema/version =
       ./version.dhall
diff --git a/schema.dhall b/schema.dhall
index 78fceb7..4115206 100644
--- a/schema.dhall
+++ b/schema.dhall
@@ -15,6 +15,21 @@ let Schema =
               , Gzip : Natural
               , Timeout : Natural
               }
+          , Mailer :
+              { Enabled : Bool
+              , Protocol : Text
+              , SMTPAddr : Text
+              , SMTPPort : Natural
+              , ForceTrustServerCert : Bool
+              , EnableHELO : Bool
+              , HELOHostname : Text
+              , Auth : Text
+              , From : Text
+              , User : Text
+              , Password : Text
+              , SubjectPrefix : Text
+              , SendPlainText : Bool
+              }
           , AppName : Text
           , LiveMode : Bool
           , DevelMode : Bool
@@ -44,6 +59,15 @@ let Schema =
             , Gzip = 0
             , Timeout = 0
             }
+          , Mailer =
+            { Enabled = False
+            , Protocol = "smtps"
+            , SMTPPort = 465
+            , ForceTrustServerCert = False
+            , EnableHELO = False
+            , SubjectPrefix = "pcmt - "
+            , SendPlainText = True
+            }
           , AppName = "pcmt"
           , LiveMode = False
           , DevelMode = False
diff --git a/validate.dhall b/validate.dhall
index 192f198..018c039 100644
--- a/validate.dhall
+++ b/validate.dhall
@@ -5,7 +5,7 @@ let Prelude =
 
 let Schema =
         ./schema.dhall
-          sha256:99dc461563042c4c4df92a8ce5a66842496be9fb2303bd0d7bf344417888cf61
+          sha256:1aa8c2f42fc6fc3055a35c1285314340f934aa50226c6cdc96f8d19471a84835
       ? ./schema.dhall
 
 let Schema/validate
@@ -13,13 +13,20 @@ let Schema/validate
     =
       -- | define validation.
       \(c : Schema.Type) ->
-        let expected = { validPort = True }
+        let expected = { validPort = True, validSMTPPort = True }
 
         let actual =
               { validPort =
                   -- | make sure port number belongs to the <1;65535> range.
                       Prelude.Natural.lessThanEqual 1 c.Port
                   &&  Prelude.Natural.lessThanEqual c.Port 65535
+              , validSMTPPort =
+                  if    c.Mailer.Enabled == False
+                  then  True
+                  else      Prelude.Natural.lessThanEqual 1 c.Mailer.SMTPPort
+                        &&  Prelude.Natural.lessThanEqual
+                              c.Mailer.SMTPPort
+                              65535
               }
 
         in  expected === actual