diff --git a/Network/Mail/Mime.hs b/Network/Mail/Mime.hs
--- a/Network/Mail/Mime.hs
+++ b/Network/Mail/Mime.hs
@@ -451,6 +451,7 @@
     toQPC 10 | isText = QPCLF
     toQPC 9 = QPCTab
     toQPC 0x20 = QPCSpace
+    toQPC 46 = QPCEscape
     toQPC 61 = QPCEscape
     toQPC w
         | 33 <= w && w <= 126 = QPCPlain
diff --git a/mime-mail.cabal b/mime-mail.cabal
--- a/mime-mail.cabal
+++ b/mime-mail.cabal
@@ -1,5 +1,5 @@
 Name:                mime-mail
-Version:             0.4.8.1
+Version:             0.4.8.2
 Synopsis:            Compose MIME email messages.
 description:         Hackage documentation generation is not reliable. For up to date documentation, please see: <http://www.stackage.org/package/mime-mail>.
 Homepage:            http://github.com/snoyberg/mime-mail