diff --git a/Yst/Render.hs b/Yst/Render.hs
--- a/Yst/Render.hs
+++ b/Yst/Render.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE OverloadedStrings, ScopedTypeVariables #-}
+{-# LANGUAGE OverloadedStrings, ScopedTypeVariables, CPP #-}
 {-
 Copyright (C) 2009 John MacFarlane <jgm@berkeley.edu>
 
@@ -42,6 +42,12 @@
 #endif
 import Data.Time
 import Control.Monad
+#if MIN_VERSION_pandoc(1,14,0)
+import Text.Pandoc.Error (handleError)
+#else
+handleError :: Pandoc -> Pandoc
+handleError = id
+#endif
 
 -- | @relUrl a b@ returns a URL for @b@ relative to @a@.  So, for
 -- example, @relUrl "a" "a/b.html" = "b.html"@,
@@ -137,9 +143,9 @@
 
 converterForFormat :: Format -> String -> String
 converterForFormat f =
-  let reader = readMarkdown def{readerSmart = True}
+  let reader = handleError . readMarkdown def{readerSmart = True}
   in  case f of
-       HtmlFormat          -> writeHtmlString def . reader
+       HtmlFormat          -> writeHtmlString def{ writerHtml5 = True } . reader
        LaTeXFormat         -> writeLaTeX def . reader
        PlainFormat         -> id
        ConTeXtFormat       -> writeConTeXt def . reader
diff --git a/Yst/Types.hs b/Yst/Types.hs
--- a/Yst/Types.hs
+++ b/Yst/Types.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances, TypeSynonymInstances, CPP #-}
 {-
 Copyright (C) 2009 John MacFarlane <jgm@berkeley.edu>
 
@@ -26,9 +26,13 @@
 import Text.StringTemplate
 import Data.Aeson
 import qualified Data.Map as M
-import System.Locale (defaultTimeLocale)
 import Data.Scientific (coefficient, base10Exponent)
 import Control.Monad
+#if MIN_VERSION_time(1,5,0)
+import Data.Time.Format ( defaultTimeLocale )
+#else
+import System.Locale ( defaultTimeLocale )
+#endif
 
 data Site = Site {
     siteTitle     :: String
diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,9 @@
+yst 0.5.0.3 (released 02 Jun 2015)
+
+  * Updated to use pandoc 1.14, aeson 0.9, time 0.5.
+  * Use HTML5 in rendering pandoc.
+  * Added code to default css to collapse menu at "small" size.
+
 yst 0.5.0.2 (released 14 Mar 2015)
 
   * Improved menus, using unfolding tree instead of pop-ups.
diff --git a/demo/files/css/screen.css b/demo/files/css/screen.css
--- a/demo/files/css/screen.css
+++ b/demo/files/css/screen.css
@@ -23,3 +23,42 @@
 li > ul.tree {
   padding-left: 10px;
 }
+
+/* collapse menu at "small" size rather than phone size */
+@media (max-width: 991px) {
+    .navbar-header {
+        float: none;
+    }
+    .navbar-toggle {
+        display: block;
+    }
+    .navbar-collapse {
+        border-top: 1px solid transparent;
+        box-shadow: inset 0 1px 0 rgba(255,255,255,0.1);
+    }
+    .navbar-collapse.collapse {
+        display: none!important;
+    }
+    .navbar-nav {
+        float: none!important;
+        margin: 7.5px -15px;
+    }
+    .navbar-nav>li {
+        float: none;
+    }
+    .navbar-nav>li>a {
+        padding-top: 10px;
+        padding-bottom: 10px;
+    }
+    .navbar-text {
+        float: none;
+        margin: 15px 0;
+    }
+    /* since 3.1.0 */
+    .navbar-collapse.collapse.in {
+        display: block!important;
+    }
+    .collapsing {
+        overflow: hidden!important;
+    }
+}
diff --git a/yst.cabal b/yst.cabal
--- a/yst.cabal
+++ b/yst.cabal
@@ -1,5 +1,5 @@
 name:                yst
-version:             0.5.0.2
+version:             0.5.0.3
 Tested-With:         GHC == 7.8.3
 Cabal-version:       >= 1.8
 build-type:          Simple
@@ -52,16 +52,15 @@
                      Yst.Render, Yst.Build, Yst.CSV, Yst.Sqlite3
   build-depends:     base >=3 && < 5, unordered-containers,
                      HStringTemplate >= 0.6.1 && < 0.6.9 || > 0.6.11 && < 0.9,
-                     yaml, csv, aeson >= 0.7 && < 0.9, text,
+                     yaml, csv, aeson >= 0.7 && < 0.10, text,
                      scientific >= 0.2 && < 0.4,
                      filepath, containers, directory, time,
                      old-locale, old-time, parsec,
                      lucid >= 2.9 && < 2.10,
-                     pandoc >= 1.10 && < 1.14,
+                     pandoc >= 1.10 && < 1.15,
                      split, HDBC, HDBC-sqlite3
   extensions:        CPP
   if impl(ghc >= 6.12)
     ghc-options:     -Wall -threaded -fno-warn-orphans -fno-warn-unused-do-bind
   else
     ghc-options:     -Wall -threaded -fno-warn-orphans
-  ghc-prof-options:  -auto-all -caf-all