diff -Nru rednotebook-2.20+ds/CHANGELOG.md rednotebook-2.21+ds/CHANGELOG.md
--- rednotebook-2.20+ds/CHANGELOG.md	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/CHANGELOG.md	2020-12-07 08:45:53.000000000 +0000
@@ -1,3 +1,7 @@
+# 2.21 (2020-12-07)
+* Update MathJax to version 3 (#515, @dgcampea).
+* Fix date references in CEF-based HtmlView (#544, Paweł Żukowski).
+
 # 2.20 (2020-08-03)
 * Fix drag and drop (#492, @dgcampea).
 * Fix external previews (Eric Chazan).
diff -Nru rednotebook-2.20+ds/data/rednotebook.appdata.xml rednotebook-2.21+ds/data/rednotebook.appdata.xml
--- rednotebook-2.20+ds/data/rednotebook.appdata.xml	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/data/rednotebook.appdata.xml	2020-12-07 08:45:53.000000000 +0000
@@ -2,7 +2,7 @@
 <component type="desktop">
   <id>rednotebook.desktop</id>
   <metadata_license>CC0-1.0</metadata_license>
-  <project_license>GPL-3.0+</project_license>
+  <project_license>GPL-2.0-or-later</project_license>
   <name>RedNotebook</name>
   <developer_name>Jendrik Seipp</developer_name>
   <summary>Graphical diary and journal</summary>
diff -Nru rednotebook-2.20+ds/debian/changelog rednotebook-2.21+ds/debian/changelog
--- rednotebook-2.20+ds/debian/changelog	2020-10-31 17:52:35.000000000 +0000
+++ rednotebook-2.21+ds/debian/changelog	2020-12-15 08:46:02.000000000 +0000
@@ -1,3 +1,11 @@
+rednotebook (2.21+ds-1) unstable; urgency=medium
+
+  * Team upload.
+  * New upstream version 2.21.
+  * Update standards-version to 4.5.1 - No changes required.
+
+ -- Phil Wyett <philip.wyett@kathenas.org>  Tue, 15 Dec 2020 08:46:02 +0000
+
 rednotebook (2.20+ds-1.1) unstable; urgency=medium
 
   * Non-maintainer upload.
diff -Nru rednotebook-2.20+ds/debian/control rednotebook-2.21+ds/debian/control
--- rednotebook-2.20+ds/debian/control	2020-09-12 19:48:21.000000000 +0000
+++ rednotebook-2.21+ds/debian/control	2020-12-15 08:46:02.000000000 +0000
@@ -2,7 +2,7 @@
 Maintainer: Jendrik Seipp <jendrikseipp@gmail.com>
 Section: text
 Priority: optional
-Standards-Version: 4.5.0
+Standards-Version: 4.5.1
 Rules-Requires-Root: no
 Homepage: https://rednotebook.app
 Vcs-Git: https://github.com/jendrikseipp/rednotebook.git
diff -Nru rednotebook-2.20+ds/dev/check-style.sh rednotebook-2.21+ds/dev/check-style.sh
--- rednotebook-2.20+ds/dev/check-style.sh	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/dev/check-style.sh	2020-12-07 08:45:53.000000000 +0000
@@ -9,13 +9,13 @@
 
 # E203: whitespace before ':' (not compliant with PEP 8)
 # E402: module level import not at top of file
-python3 -m flake8 --exclude=external --extend-ignore=E203,E402 --max-line-length=110 --builtins="_" rednotebook tests setup.py
+python3 -m flake8 --exclude=external --extend-ignore=E203,E402 --max-line-length=110 --builtins="_" rednotebook tests setup.py dev/whitelist.py
 
 isort --check-only rednotebook/ tests/
 
 python3 -m pyupgrade --py3-plus `find rednotebook tests -name "*.py" -not -path "*external*"`
 
-./dev/find-dead-code.sh
+python3 -m vulture --exclude=external rednotebook dev/whitelist.py
 
 python3 setup.py build_trans
 
diff -Nru rednotebook-2.20+ds/dev/find-dead-code.sh rednotebook-2.21+ds/dev/find-dead-code.sh
--- rednotebook-2.20+ds/dev/find-dead-code.sh	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/dev/find-dead-code.sh	1970-01-01 00:00:00.000000000 +0000
@@ -1,10 +0,0 @@
-#! /bin/bash
-
-set -euxo pipefail
-
-cd "$(dirname "$0")"
-cd ..
-
-python3 -m flake8 --extend-ignore=E402 dev/whitelist.py
-python3 dev/whitelist.py
-python3 -m vulture --exclude=external rednotebook dev/whitelist.py
diff -Nru rednotebook-2.20+ds/dev/mac-homebrew.txt rednotebook-2.21+ds/dev/mac-homebrew.txt
--- rednotebook-2.20+ds/dev/mac-homebrew.txt	1970-01-01 00:00:00.000000000 +0000
+++ rednotebook-2.21+ds/dev/mac-homebrew.txt	2020-12-07 08:45:53.000000000 +0000
@@ -0,0 +1,28 @@
+Installing RedNotebook from source on macOS
+===========================================
+
+(many thanks to Peter Green for documenting this at
+https://gist.github.com/pmgreen/a1bf2c7015cb2a70d73e5e66bb84885e)
+
+Of the three mac installation methods listed on the Rednotebook downloads page, these got the closest:
+https://jarrousse.org/installing-rednotebook-from-source-on-mac-os-x/
+
+Here's a summary of modified steps ...
+
+$ git clone https://github.com/jendrikseipp/rednotebook
+$ brew install gtk # <= using brew to install gtk worked
+$ brew install pygobject3 glib libffi cairo gtksourceview3
+$ brew install atk librsvg # <= don't install gdk-pixbuf at this step
+$ brew install gsettings-desktop-schemas adwaita-icon-theme
+$ brew install enchant
+export LANG=en_US.UTF-8
+export LC_ALL=en_US.UTF-8
+$ cd ~/path/to/rednotebook
+$ pip3 install --user .
+
+In Automator (run as bash shell script) ...
+
+export PATH=/usr/local/bin:$PATH
+export LANG=en_US.UTF-8
+export LC_ALL=en_US.UTF-8
+/Users/me/path/rednotebook
diff -Nru rednotebook-2.20+ds/.github/workflows/ubuntu-20.04.yml rednotebook-2.21+ds/.github/workflows/ubuntu-20.04.yml
--- rednotebook-2.20+ds/.github/workflows/ubuntu-20.04.yml	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/.github/workflows/ubuntu-20.04.yml	1970-01-01 00:00:00.000000000 +0000
@@ -1,33 +0,0 @@
-name: Ubuntu-20.04
-
-# see https://github.community/t5/GitHub-Actions/How-to-trigger-an-action-on-push-or-pull-request-but-not-both/m-p/35805
-on:
-  push:
-    branches:
-    - master
-  pull_request:
-    branches:
-    - master
-
-jobs:
-  build:
-
-    runs-on: ubuntu-20.04
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Show environment
-      run: |
-        python --version
-        python3 --version
-        python3 -c "import multiprocessing as m; print('CPUs:', m.cpu_count())"
-
-    - name: Install dependencies
-      run: |
-        sudo apt-get -y update
-        sudo apt-get -y install -qq gir1.2-gdkpixbuf-2.0 gir1.2-glib-2.0 gir1.2-gtk-3.0 gir1.2-pango-1.0 gir1.2-webkit2-4.0 python3 python3-enchant python3-gi python3-yaml tox
-
-    - name: Run tests
-      run: |
-        tox -e py
diff -Nru rednotebook-2.20+ds/.github/workflows/ubuntu.yml rednotebook-2.21+ds/.github/workflows/ubuntu.yml
--- rednotebook-2.20+ds/.github/workflows/ubuntu.yml	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/.github/workflows/ubuntu.yml	2020-12-07 08:45:53.000000000 +0000
@@ -8,6 +8,10 @@
   pull_request:
     branches:
     - master
+  schedule:
+    # Run workflow every morning (* needs quotes).
+    - cron: '0 4 * * *'
+
 
 jobs:
   build:
diff -Nru rednotebook-2.20+ds/MANIFEST.in rednotebook-2.21+ds/MANIFEST.in
--- rednotebook-2.20+ds/MANIFEST.in	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/MANIFEST.in	2020-12-07 08:45:53.000000000 +0000
@@ -1,3 +1,7 @@
+include *.md
+include LICENSE
+include pyproject.toml
+include run
 include po/*.pot
 include po/*.po
 include rednotebook/images/*.png
@@ -6,6 +10,3 @@
 include rednotebook/files/*.glade
 include rednotebook/files/*.lang
 include rednotebook/files/*.xml
-include *.md
-include LICENSE
-include run
diff -Nru rednotebook-2.20+ds/po/rednotebook.pot rednotebook-2.21+ds/po/rednotebook.pot
--- rednotebook-2.20+ds/po/rednotebook.pot	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/po/rednotebook.pot	2020-12-07 08:45:53.000000000 +0000
@@ -8,7 +8,7 @@
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2020-08-03 01:12+0200\n"
+"POT-Creation-Date: 2020-12-07 09:45+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -43,7 +43,7 @@
 msgid "unknown"
 msgstr ""
 
-#: ../rednotebook/util/markup.py:140 ../rednotebook/gui/categories.py:47
+#: ../rednotebook/util/markup.py:129 ../rednotebook/gui/categories.py:47
 #: ../rednotebook/gui/clouds.py:213 ../rednotebook/help.py:24
 msgid "Tags"
 msgstr ""
@@ -250,7 +250,7 @@
 msgstr ""
 
 #: ../rednotebook/gui/customwidgets.py:334
-#: ../rednotebook/gui/main_window.py:679
+#: ../rednotebook/gui/main_window.py:683
 msgid "Template"
 msgstr ""
 
@@ -400,157 +400,157 @@
 msgid "Hide \"%s\" from clouds"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:92
+#: ../rednotebook/gui/menu.py:91
 msgid "_Journal"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:98
+#: ../rednotebook/gui/menu.py:97
 msgid "Create a new journal. The old one will be saved"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:106
+#: ../rednotebook/gui/menu.py:105
 msgid "Load an existing journal. The old journal will be saved"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:116
+#: ../rednotebook/gui/menu.py:115
 msgid ""
 "Save journal at a new location. The old journal files will also be saved"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:124
+#: ../rednotebook/gui/menu.py:123
 msgid "Export"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:126
+#: ../rednotebook/gui/menu.py:125
 msgid "Open the export assistant"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:133
+#: ../rednotebook/gui/menu.py:132
 msgid "_Backup"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:135
+#: ../rednotebook/gui/menu.py:134
 msgid "Save all the data in a zip archive"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:141
+#: ../rednotebook/gui/menu.py:140
 msgid "S_tatistics"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:143
+#: ../rednotebook/gui/menu.py:142
 msgid "Show some statistics about the journal"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:151
+#: ../rednotebook/gui/menu.py:150
 msgid "Shutdown RedNotebook. It will not be sent to the tray."
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:154
+#: ../rednotebook/gui/menu.py:153
 msgid "_Edit"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:160
+#: ../rednotebook/gui/menu.py:159
 msgid "Undo text or tag edits"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:168
+#: ../rednotebook/gui/menu.py:167
 msgid "Redo text or tag edits"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:213
+#: ../rednotebook/gui/menu.py:212
 msgid "Underline misspelled words"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:228
+#: ../rednotebook/gui/menu.py:227
 msgid "_Help"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:232
+#: ../rednotebook/gui/menu.py:231
 msgid "Contents"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:234
+#: ../rednotebook/gui/menu.py:233
 msgid "Open the RedNotebook documentation"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:240
+#: ../rednotebook/gui/menu.py:239
 msgid "Get Help Online"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:242
+#: ../rednotebook/gui/menu.py:241
 msgid "Browse answered questions or ask a new one"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:248
+#: ../rednotebook/gui/menu.py:247
 msgid "Translate RedNotebook"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:250
+#: ../rednotebook/gui/menu.py:249
 msgid "Connect to the Launchpad website to help translate RedNotebook"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:256
+#: ../rednotebook/gui/menu.py:255
 msgid "Report a Problem"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:258
+#: ../rednotebook/gui/menu.py:257
 msgid "Fill out a short form about the problem"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:279
+#: ../rednotebook/gui/menu.py:278
 msgid "Wrong directory"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:283 ../rednotebook/journal.py:215
+#: ../rednotebook/gui/menu.py:282 ../rednotebook/journal.py:215
 msgid "You cannot use this directory for your journal:"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:290
+#: ../rednotebook/gui/menu.py:289
 msgid "Please select an empty directory."
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:295
+#: ../rednotebook/gui/menu.py:294
 msgid "This directory contains no journal files:"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:314
+#: ../rednotebook/gui/menu.py:313
 msgid "Journals are saved in a directory, not in a single file."
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:315
+#: ../rednotebook/gui/menu.py:314
 msgid "The directory name will be the title of the new journal."
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:318
+#: ../rednotebook/gui/menu.py:317
 msgid "Select an empty folder for your new journal"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:324
+#: ../rednotebook/gui/menu.py:323
 msgid "Select an existing journal directory"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:325
+#: ../rednotebook/gui/menu.py:324
 msgid "The directory should contain your journal's data files"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:338
+#: ../rednotebook/gui/menu.py:337
 msgid "Select an empty folder for the new location of your journal"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:339
+#: ../rednotebook/gui/menu.py:338
 msgid "The directory name will be the new title of the journal"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:399
+#: ../rednotebook/gui/menu.py:398
 msgid "RedNotebook Documentation"
 msgstr ""
 
-#: ../rednotebook/gui/menu.py:424
+#: ../rednotebook/gui/menu.py:423
 msgid "Contributors:"
 msgstr ""
 
 #. Translators: TRANSLATORS: Replace this string with your names, one name per line.
-#: ../rednotebook/gui/menu.py:425 tmp/main_window.glade.h:2
+#: ../rednotebook/gui/menu.py:424 tmp/main_window.glade.h:2
 msgid "translator-credits"
 msgstr ""
 
@@ -691,19 +691,19 @@
 msgid "Format the selected text or tag"
 msgstr ""
 
-#: ../rednotebook/gui/main_window.py:181
+#: ../rednotebook/gui/main_window.py:184
 msgid "Preview in Browser"
 msgstr ""
 
-#: ../rednotebook/gui/main_window.py:328
+#: ../rednotebook/gui/main_window.py:331
 msgid "Show RedNotebook"
 msgstr ""
 
-#: ../rednotebook/gui/main_window.py:585
+#: ../rednotebook/gui/main_window.py:589
 msgid "No directory selected."
 msgstr ""
 
-#: ../rednotebook/gui/main_window.py:683
+#: ../rednotebook/gui/main_window.py:687
 msgid ""
 "Insert this weekday's template. Click the arrow on the right for more options"
 msgstr ""
diff -Nru rednotebook-2.20+ds/pyproject.toml rednotebook-2.21+ds/pyproject.toml
--- rednotebook-2.20+ds/pyproject.toml	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/pyproject.toml	2020-12-07 08:45:53.000000000 +0000
@@ -1,3 +1,7 @@
+[build-system]
+requires = ["setuptools >= 40.6.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
 # NOTE: you have to use single-quoted strings in TOML for regular expressions.
 # It's the equivalent of r-strings in Python.  Multiline strings are treated as
 # verbose regular expressions by Black.  Use [ ] to denote a significant space
diff -Nru rednotebook-2.20+ds/rednotebook/gui/browser_cef.py rednotebook-2.21+ds/rednotebook/gui/browser_cef.py
--- rednotebook-2.20+ds/rednotebook/gui/browser_cef.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/rednotebook/gui/browser_cef.py	2020-12-07 08:45:53.000000000 +0000
@@ -19,7 +19,6 @@
 import ctypes
 import logging
 import sys
-import webbrowser
 
 from gi.repository import Gdk, GObject, Gtk
 
@@ -39,14 +38,9 @@
 
 if cef:
 
-    class _RequestHandler:
-        def OnBeforeBrowse(self, browser, frame, request, **_):
-            """Called when the loading state has changed."""
-            webbrowser.open(request.GetUrl())
-            # Cancel request.
-            return True
-
     class HtmlView(Gtk.DrawingArea):
+        NOTEBOOK_URL = "file:///"
+
         """
         Loading HTML strings only works if we pass the `url` parameter to
         CreateBrowserSync.
@@ -76,7 +70,7 @@
 
         def load_html(self, html):
             if self._browser:
-                self._browser.GetMainFrame().LoadString(html, "file:///dummy/")
+                self._browser.GetMainFrame().LoadString(html, self.NOTEBOOK_URL)
             else:
                 self._initial_html = html
 
@@ -107,11 +101,32 @@
             window_info = cef.WindowInfo()
             self._win32_handle = self.get_handle()
             window_info.SetAsChild(self._win32_handle)
-            self._browser = cef.CreateBrowserSync(window_info, url="file:///dummy/")
-            self._browser.SetClientHandler(_RequestHandler())
+            self._browser = cef.CreateBrowserSync(window_info, url=self.NOTEBOOK_URL)
+            self._browser.SetClientCallback("OnBeforeBrowse", self.on_before_browse)
+            self._browser.SetClientCallback("OnAddressChange", self.on_address_change)
             self.load_html(self._initial_html)
             self._initial_html = None
 
+        @GObject.Signal(name="on-url-clicked", arg_types=(str,))
+        def url_clicked_signal(self, url):
+            logging.debug("Emitting on-url-clicked signal: %s", url)
+
+        def on_before_browse(self, browser, frame, request, **_):
+            url = request.GetUrl()
+            # For some reason GetUrl() appends slash to the returned URL so we need to compensate for it:
+            # (https://bugs.chromium.org/p/chromium/issues/detail?id=339054 might be the cause)
+            if url == self.NOTEBOOK_URL + "/":
+                # On first invocation the url points to dummy NOTEBOOK_URL.
+                # There is no reason to emit signal for it.
+                return False
+            self.url_clicked_signal.emit(url)
+            return True
+
+        def on_address_change(self, browser, frame, url):
+            if url == self.NOTEBOOK_URL:
+                return
+            self.url_clicked_signal.emit(url)
+
         def on_configure(self, *_):
             if self._browser:
                 self._browser.NotifyMoveOrResizeStarted()
diff -Nru rednotebook-2.20+ds/rednotebook/gui/main_window.py rednotebook-2.21+ds/rednotebook/gui/main_window.py
--- rednotebook-2.20+ds/rednotebook/gui/main_window.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/rednotebook/gui/main_window.py	2020-12-07 08:45:53.000000000 +0000
@@ -173,6 +173,9 @@
                     pass
 
             self.html_editor = Preview(self.journal)
+            self.html_editor.connect(
+                "on-url-clicked", lambda _, url: self.navigate_to_uri(url)
+            )
             self.text_vbox.pack_start(self.html_editor, True, True, 0)
         else:
             self.html_editor = mock.MagicMock()
@@ -550,18 +553,19 @@
             action = decision.get_navigation_action()
             if action.is_user_gesture():
                 uri = action.get_request().get_uri()
-                logging.info('Clicked URI "%s"' % uri)
-
-                if urls.is_entry_reference_uri(uri):
-                    self.navigate_to_referenced_entry(uri)
-                else:
-                    urls.open_url(uri)
-
+                self.navigate_to_uri(uri)
                 decision.ignore()
 
         # Stop processing this event.
         return True
 
+    def navigate_to_uri(self, uri):
+        logging.info('Navigating to URI "%s"' % uri)
+        if urls.is_entry_reference_uri(uri):
+            self.navigate_to_referenced_entry(uri)
+        else:
+            urls.open_url(uri)
+
     def navigate_to_referenced_entry(self, entry_reference_uri):
         entry_reference_uri = urllib.parse.urlparse(entry_reference_uri)
         date = dates.get_date_from_date_string(entry_reference_uri.fragment)
diff -Nru rednotebook-2.20+ds/rednotebook/gui/menu.py rednotebook-2.21+ds/rednotebook/gui/menu.py
--- rednotebook-2.20+ds/rednotebook/gui/menu.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/rednotebook/gui/menu.py	2020-12-07 08:45:53.000000000 +0000
@@ -57,8 +57,8 @@
         <menuitem action="CheckSpelling"/>
         <menuitem action="Options"/>
     </menu>
-    %s
-    %s
+    {}
+    {}
     <menu action="HelpMenu">
         <menuitem action="Help"/>
         <separator/>
@@ -69,9 +69,8 @@
         <menuitem action="Info"/>
     </menu>
 </menubar>
-</ui>""" % (
-    insert_menu.MENUBAR_XML,
-    format_menu.MENUBAR_XML,
+</ui>""".format(
+    insert_menu.MENUBAR_XML, format_menu.MENUBAR_XML,
 )
 
 
diff -Nru rednotebook-2.20+ds/rednotebook/info.py rednotebook-2.21+ds/rednotebook/info.py
--- rednotebook-2.20+ds/rednotebook/info.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/rednotebook/info.py	2020-12-07 08:45:53.000000000 +0000
@@ -28,10 +28,10 @@
 
 program_name = "RedNotebook"
 tagline = _("A Desktop Journal")
-version = "2.20"
+version = "2.21"
 author = "Jendrik Seipp"
 author_mail = "jendrikseipp@gmail.com"
-copyright_ = "Copyright (c) 2008-2019 Jendrik Seipp"
+copyright_ = "Copyright (c) 2008-2020 Jendrik Seipp"
 url = "https://rednotebook.app"
 downloads_url = "https://rednotebook.app/downloads.html"
 answers_url = "https://answers.launchpad.net/rednotebook"
diff -Nru rednotebook-2.20+ds/rednotebook/util/markup.py rednotebook-2.21+ds/rednotebook/util/markup.py
--- rednotebook-2.20+ds/rednotebook/util/markup.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/rednotebook/util/markup.py	2020-12-07 08:45:53.000000000 +0000
@@ -108,7 +108,7 @@
 
 # MathJax
 FORMULAS_SUPPORTED = True
-MATHJAX_FILE = "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js"
+MATHJAX_FILE = "https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js"
 
 # Explicitly setting inlineMath: [ ['\\(','\\)'] ] doesn't work.
 # Using defaults:
@@ -116,18 +116,7 @@
 #       inlineMath:  [['\(','\)']]
 MATHJAX_DELIMITERS = ["$$", "\\(", "\\)", r"\\[", "\\]"]
 MATHJAX = """\
-<script type="text/x-mathjax-config">
-  MathJax.Hub.Config({{
-    messageStyle: "none",
-    config: ["MMLorHTML.js"],
-    jax: ["input/TeX","input/MathML","output/HTML-CSS","output/NativeMML"],
-    tex2jax: {{}},
-    extensions: ["tex2jax.js","mml2jax.js","MathMenu.js","MathZoom.js"],
-    TeX: {{
-      extensions: ["AMSmath.js","AMSsymbols.js","noErrors.js","noUndefined.js"]
-    }}
-  }});
-</script>
+<!--MathJax included-->
 <script type="text/javascript" src="{MATHJAX_FILE}"></script>
 """.format(
     **locals()
diff -Nru rednotebook-2.20+ds/setup.py rednotebook-2.21+ds/setup.py
--- rednotebook-2.20+ds/setup.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/setup.py	2020-12-07 08:45:53.000000000 +0000
@@ -136,6 +136,19 @@
         ("share/metainfo", ["data/rednotebook.appdata.xml"]),
     ],
     "cmdclass": cmdclass,
+    "extras_require": {
+        "dev_style": [
+            "black==19.10b0",
+            "flake8",
+            "flake8-2020",
+            "flake8-bugbear",
+            "flake8-comprehensions",
+            "flake8-executable",
+            "isort>=5.0,<5.1",
+            "pyupgrade==2.6.2",
+            "vulture==1.6",
+        ],
+    },
 }
 
 if __name__ == "__main__":
diff -Nru rednotebook-2.20+ds/tests/test_markup.py rednotebook-2.21+ds/tests/test_markup.py
--- rednotebook-2.20+ds/tests/test_markup.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/tests/test_markup.py	2020-12-07 08:45:53.000000000 +0000
@@ -234,7 +234,7 @@
 
     def test_mathjax(self, process):
         document = process("$$x^3$$")
-        assert r'<script type="text/x-mathjax-config">' in document
+        assert r"<!--MathJax included-->" in document
 
 
 class TestGetTexExportConfig:
diff -Nru rednotebook-2.20+ds/tox.ini rednotebook-2.21+ds/tox.ini
--- rednotebook-2.20+ds/tox.ini	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/tox.ini	2020-12-07 08:45:53.000000000 +0000
@@ -7,32 +7,21 @@
   pytest
 commands =
   python -m pytest
+  python dev/whitelist.py
 sitepackages = true
 
 [testenv:style]
 skipsdist = true
-deps =
-  black
-  flake8
-  flake8-2020
-  flake8-bugbear
-  flake8-comprehensions
-  flake8-executable
-  isort>=5.0,<5.1
-  pyupgrade==2.6.2
-  vulture==1.6
+extras = dev_style
 commands =
   bash dev/check-style.sh
 whitelist_externals =
   bash
-sitepackages = true
+sitepackages = false
 
 [testenv:fix-style]
 skipsdist = true
-deps =
-  black
-  isort>=5.0,<5.1
-  pyupgrade==2.6.2
+extras = dev_style
 commands =
   black .
   isort rednotebook/ tests/
diff -Nru rednotebook-2.20+ds/win/hook-cefpython3.py rednotebook-2.21+ds/win/hook-cefpython3.py
--- rednotebook-2.20+ds/win/hook-cefpython3.py	2020-08-02 23:12:55.000000000 +0000
+++ rednotebook-2.21+ds/win/hook-cefpython3.py	2020-12-07 08:45:53.000000000 +0000
@@ -69,7 +69,7 @@
 def get_cefpython_modules():
     """Get all cefpython Cython modules in the cefpython3 package.
     It returns a list of names without file extension. Eg.
-    'cefpython_py27'. """
+    'cefpython_py27'."""
     pyds = glob.glob(os.path.join(CEFPYTHON3_DIR, "cefpython_py*" + CYTHON_MODULE_EXT))
     assert len(pyds) > 1, "Missing cefpython3 Cython modules"
     modules = []
@@ -82,10 +82,10 @@
 
 def get_excluded_cefpython_modules():
     """CEF Python package includes Cython modules for various Python
-       versions. When using Python 2.7 pyinstaller should not
-       bundle modules for eg. Python 3.6, otherwise it will
-       cause to include Python 3 dll dependencies. Returns a list
-       of fully qualified names eg. 'cefpython3.cefpython_py27'."""
+    versions. When using Python 2.7 pyinstaller should not
+    bundle modules for eg. Python 3.6, otherwise it will
+    cause to include Python 3 dll dependencies. Returns a list
+    of fully qualified names eg. 'cefpython3.cefpython_py27'."""
     pyver = "".join(map(str, sys.version_info[:2]))
     pyver_string = "py%s" % pyver
     modules = get_cefpython_modules()