diff --git a/openlp/core/lib/db.py b/openlp/core/lib/db.py
index 7ae3cdc6f..3decb0a3b 100644
--- a/openlp/core/lib/db.py
+++ b/openlp/core/lib/db.py
@@ -68,9 +68,11 @@ def get_db_path(plugin_name, db_file_name=None):
     :return: The path to the database as type str
     """
     if db_file_name is None:
-        return 'sqlite:///%s/%s.sqlite' % (AppLocation.get_section_data_path(plugin_name), plugin_name)
+        return 'sqlite:///{path}/{plugin}.sqlite'.format(path=AppLocation.get_section_data_path(plugin_name),
+                                                         plugin=plugin_name)
     else:
-        return 'sqlite:///%s/%s' % (AppLocation.get_section_data_path(plugin_name), db_file_name)
+        return 'sqlite:///{path}/{name}'.format(path=AppLocation.get_section_data_path(plugin_name),
+                                                name=db_file_name)
 
 
 def handle_db_error(plugin_name, db_file_name):
@@ -82,10 +84,10 @@ def handle_db_error(plugin_name, db_file_name):
     :return: None
     """
     db_path = get_db_path(plugin_name, db_file_name)
-    log.exception('Error loading database: %s', db_path)
+    log.exception('Error loading database: {db}'.format(db=db_path))
     critical_error_message_box(translate('OpenLP.Manager', 'Database Error'),
-                               translate('OpenLP.Manager', 'OpenLP cannot load your database.\n\nDatabase: %s')
-                               % db_path)
+                               translate('OpenLP.Manager',
+                                         'OpenLP cannot load your database.\n\nDatabase: {db}').format(db=db_path))
 
 
 def init_url(plugin_name, db_file_name=None):
@@ -101,10 +103,11 @@ def init_url(plugin_name, db_file_name=None):
     if db_type == 'sqlite':
         db_url = get_db_path(plugin_name, db_file_name)
     else:
-        db_url = '%s://%s:%s@%s/%s' % (db_type, urlquote(settings.value('db username')),
-                                       urlquote(settings.value('db password')),
-                                       urlquote(settings.value('db hostname')),
-                                       urlquote(settings.value('db database')))
+        db_url = '{type}://{user}:{password}@{host}/{db}'.format(type=db_type,
+                                                                 user=urlquote(settings.value('db username')),
+                                                                 password=urlquote(settings.value('db password')),
+                                                                 host=urlquote(settings.value('db hostname')),
+                                                                 db=urlquote(settings.value('db database')))
     settings.endGroup()
     return db_url
 
@@ -157,10 +160,10 @@ def upgrade_db(url, upgrade):
         return version, upgrade.__version__
     version += 1
     try:
-        while hasattr(upgrade, 'upgrade_%d' % version):
-            log.debug('Running upgrade_%d', version)
+        while hasattr(upgrade, 'upgrade_{version:d}'.format(version=version)):
+            log.debug('Running upgrade_{version:d}'.format(version=version))
             try:
-                upgrade_func = getattr(upgrade, 'upgrade_%d' % version)
+                upgrade_func = getattr(upgrade, 'upgrade_{version:d}'.format(version=version))
                 upgrade_func(session, metadata)
                 session.commit()
                 # Update the version number AFTER a commit so that we are sure the previous transaction happened
@@ -168,8 +171,8 @@ def upgrade_db(url, upgrade):
                 session.commit()
                 version += 1
             except (SQLAlchemyError, DBAPIError):
-                log.exception('Could not run database upgrade script "upgrade_%s", upgrade process has been halted.',
-                              version)
+                log.exception('Could not run database upgrade script '
+                              '"upgrade_{version:d}", upgrade process has been halted.'.format(version=version))
                 break
     except (SQLAlchemyError, DBAPIError):
         version_meta = Metadata.populate(key='version', value=int(upgrade.__version__))
@@ -242,9 +245,10 @@ class Manager(object):
                 critical_error_message_box(
                     translate('OpenLP.Manager', 'Database Error'),
                     translate('OpenLP.Manager', 'The database being loaded was created in a more recent version of '
-                              'OpenLP. The database is version %d, while OpenLP expects version %d. The database will '
-                              'not be loaded.\n\nDatabase: %s') % (db_ver, up_ver, self.db_url)
-                )
+                              'OpenLP. The database is version {db_ver}, while OpenLP expects version {db_up}. '
+                              'The database will not be loaded.\n\nDatabase: {db_name}').format(db_ver=db_ver,
+                                                                                                db_up=up_ver,
+                                                                                                db_name=self.db_url))
                 return
         if not session:
             try:
@@ -460,7 +464,7 @@ class Manager(object):
                     raise
             except InvalidRequestError:
                 self.session.rollback()
-                log.exception('Failed to delete %s records', object_class.__name__)
+                log.exception('Failed to delete {name} records'.format(name=object_class.__name__))
                 return False
             except:
                 self.session.rollback()
diff --git a/openlp/core/lib/filedialog.py b/openlp/core/lib/filedialog.py
index 823567a37..249f7959d 100644
--- a/openlp/core/lib/filedialog.py
+++ b/openlp/core/lib/filedialog.py
@@ -50,7 +50,8 @@ class FileDialog(QtWidgets.QFileDialog):
                 log.info('File not found. Attempting to unquote.')
                 file = parse.unquote(file)
                 if not os.path.exists(file):
-                    log.error('File %s not found.' % file)
+                    log.error('File {text} not found.'.format(text=file))
+                    # TODO: Test with UiStrings() before converting to python3 strings
                     QtWidgets.QMessageBox.information(parent, UiStrings().FileNotFound,
                                                       UiStrings().FileNotFoundMessage % file)
                     continue
diff --git a/openlp/core/lib/htmlbuilder.py b/openlp/core/lib/htmlbuilder.py
index 812680027..f0d8ddef2 100644
--- a/openlp/core/lib/htmlbuilder.py
+++ b/openlp/core/lib/htmlbuilder.py
@@ -396,6 +396,7 @@ from openlp.core.lib.theme import BackgroundType, BackgroundGradientType, Vertic
 
 log = logging.getLogger(__name__)
 
+# TODO: Verify where this is used before converting to python3
 HTMLSRC = """
 <!DOCTYPE html>
 <html>
@@ -564,13 +565,13 @@ def build_html(item, screen, is_live, background, image=None, plugins=None):
     theme_data = item.theme_data
     # Image generated and poked in
     if background:
-        bgimage_src = 'src="data:image/png;base64,%s"' % background
+        bgimage_src = 'src="data:image/png;base64,{image}"'.format(image=background)
     elif item.bg_image_bytes:
-        bgimage_src = 'src="data:image/png;base64,%s"' % item.bg_image_bytes
+        bgimage_src = 'src="data:image/png;base64,{image}"'.format(image=item.bg_image_bytes)
     else:
         bgimage_src = 'style="display:none;"'
     if image:
-        image_src = 'src="data:image/png;base64,%s"' % image
+        image_src = 'src="data:image/png;base64,{image}"'.format(image=image)
     else:
         image_src = 'style="display:none;"'
     css_additions = ''
@@ -601,7 +602,7 @@ def webkit_version():
     """
     try:
         webkit_ver = float(QtWebKit.qWebKitVersion())
-        log.debug('Webkit version = %s' % webkit_ver)
+        log.debug('Webkit version = {version}'.format(version=webkit_ver))
     except AttributeError:
         webkit_ver = 0
     return webkit_ver
@@ -621,23 +622,25 @@ def build_background_css(item, width):
         if theme.background_type == BackgroundType.to_string(BackgroundType.Transparent):
             background = ''
         elif theme.background_type == BackgroundType.to_string(BackgroundType.Solid):
-            background = 'background-color: %s' % theme.background_color
+            background = 'background-color: {theme}'.format(theme=theme.background_color)
         else:
             if theme.background_direction == BackgroundGradientType.to_string(BackgroundGradientType.Horizontal):
-                background = 'background: -webkit-gradient(linear, left top, left bottom, from(%s), to(%s)) fixed' \
-                    % (theme.background_start_color, theme.background_end_color)
+                background = 'background: -webkit-gradient(linear, left top, left bottom, from({start}), to({end})) ' \
+                    'fixed'.format(start=theme.background_start_color, end=theme.background_end_color)
             elif theme.background_direction == BackgroundGradientType.to_string(BackgroundGradientType.LeftTop):
-                background = 'background: -webkit-gradient(linear, left top, right bottom, from(%s), to(%s)) fixed' \
-                    % (theme.background_start_color, theme.background_end_color)
+                background = 'background: -webkit-gradient(linear, left top, right bottom, from({start}), to({end})) ' \
+                    'fixed'.format(start=theme.background_start_color, end=theme.background_end_color)
             elif theme.background_direction == BackgroundGradientType.to_string(BackgroundGradientType.LeftBottom):
-                background = 'background: -webkit-gradient(linear, left bottom, right top, from(%s), to(%s)) fixed' \
-                    % (theme.background_start_color, theme.background_end_color)
+                background = 'background: -webkit-gradient(linear, left bottom, right top, from({start}), to({end})) ' \
+                    'fixed'.format(start=theme.background_start_color, end=theme.background_end_color)
             elif theme.background_direction == BackgroundGradientType.to_string(BackgroundGradientType.Vertical):
-                background = 'background: -webkit-gradient(linear, left top, right top, from(%s), to(%s)) fixed' % \
-                    (theme.background_start_color, theme.background_end_color)
+                background = 'background: -webkit-gradient(linear, left top, right top, from({start}), to({end})) ' \
+                    'fixed'.format(start=theme.background_start_color, end=theme.background_end_color)
             else:
-                background = 'background: -webkit-gradient(radial, %s 50%%, 100, %s 50%%, %s, from(%s), to(%s)) fixed'\
-                    % (width, width, width, theme.background_start_color, theme.background_end_color)
+                background = 'background: -webkit-gradient(radial, {width} 50%, 100, {width} 50%, {width}, ' \
+                    'from({start}), to({end})) fixed'.format(width=width,
+                                                             start=theme.background_start_color,
+                                                             end=theme.background_end_color)
     return background
 
 
@@ -647,6 +650,7 @@ def build_lyrics_css(item):
 
     :param item: Service Item containing theme and location information
     """
+    # TODO: Verify this before converting to python3
     style = """
 .lyricstable {
     z-index: 5;
@@ -669,12 +673,13 @@ def build_lyrics_css(item):
     lyrics = ''
     lyricsmain = ''
     if theme_data and item.main:
-        lyricstable = 'left: %spx; top: %spx;' % (item.main.x(), item.main.y())
+        lyricstable = 'left: {left}px; top: {top}px;'.format(left=item.main.x(), top=item.main.y())
         lyrics = build_lyrics_format_css(theme_data, item.main.width(), item.main.height())
         lyricsmain += build_lyrics_outline_css(theme_data)
         if theme_data.font_main_shadow:
-            lyricsmain += ' text-shadow: %s %spx %spx;' % \
-                (theme_data.font_main_shadow_color, theme_data.font_main_shadow_size, theme_data.font_main_shadow_size)
+            lyricsmain += ' text-shadow: {theme} {shadow}px ' \
+                '{shadow}px;'.format(theme=theme_data.font_main_shadow_color,
+                                     shadow=theme_data.font_main_shadow_size)
     lyrics_css = style % (lyricstable, lyrics, lyricsmain)
     return lyrics_css
 
@@ -689,7 +694,9 @@ def build_lyrics_outline_css(theme_data):
         size = float(theme_data.font_main_outline_size) / 16
         fill_color = theme_data.font_main_color
         outline_color = theme_data.font_main_outline_color
-        return ' -webkit-text-stroke: %sem %s; -webkit-text-fill-color: %s; ' % (size, outline_color, fill_color)
+        return ' -webkit-text-stroke: {size}em {color}; -webkit-text-fill-color: {fill}; '.format(size=size,
+                                                                                                  color=outline_color,
+                                                                                                  fill=fill_color)
     return ''
 
 
@@ -715,13 +722,21 @@ def build_lyrics_format_css(theme_data, width, height):
         padding_bottom = '0.5em'
     else:
         padding_bottom = '0'
-    lyrics = '%s word-wrap: break-word; ' \
-             'text-align: %s; vertical-align: %s; font-family: %s; ' \
-             'font-size: %spt; color: %s; line-height: %d%%; margin: 0;' \
-             'padding: 0; padding-bottom: %s; padding-left: %spx; width: %spx; height: %spx; ' % \
-        (justify, align, valign, theme_data.font_main_name, theme_data.font_main_size,
-         theme_data.font_main_color, 100 + int(theme_data.font_main_line_adjustment), padding_bottom,
-         left_margin, width, height)
+    lyrics = '{justify} word-wrap: break-word; ' \
+        'text-align: {align}; vertical-align: {valign}; font-family: {font}; ' \
+        'font-size: {size}pt; color: {color}; line-height: {line:d}%; margin: 0;' \
+        'padding: 0; padding-bottom: {bottom}; padding-left: {left}px; width: {width}px; ' \
+        'height: {height}px; '.format(justify=justify,
+                                      align=align,
+                                      valign=valign,
+                                      font=theme_data.font_main_name,
+                                      size=theme_data.font_main_size,
+                                      color=theme_data.font_main_color,
+                                      line=100 + int(theme_data.font_main_line_adjustment),
+                                      bottom=padding_bottom,
+                                      left=left_margin,
+                                      width=width,
+                                      height=height)
     if theme_data.font_main_italics:
         lyrics += 'font-style:italic; '
     if theme_data.font_main_bold:
@@ -737,20 +752,21 @@ def build_footer_css(item, height):
     :param height:
     """
     style = """
-    left: %spx;
-    bottom: %spx;
-    width: %spx;
-    font-family: %s;
-    font-size: %spt;
-    color: %s;
+    left: {left}px;
+    bottom: {bottom}px;
+    width: {width}px;
+    font-family: {family};
+    font-size: {size}pt;
+    color: {color};
     text-align: left;
-    white-space: %s;
+    white-space: {space};
     """
     theme = item.theme_data
     if not theme or not item.footer:
         return ''
     bottom = height - int(item.footer.y()) - int(item.footer.height())
     whitespace = 'normal' if Settings().value('themes/wrap footer') else 'nowrap'
-    lyrics_html = style % (item.footer.x(), bottom, item.footer.width(),
-                           theme.font_footer_name, theme.font_footer_size, theme.font_footer_color, whitespace)
+    lyrics_html = style.format(left=item.footer.x(), bottom=bottom, width=item.footer.width(),
+                               family=theme.font_footer_name, size=theme.font_footer_size,
+                               color=theme.font_footer_color, space=whitespace)
     return lyrics_html
diff --git a/openlp/core/lib/imagemanager.py b/openlp/core/lib/imagemanager.py
index 0d0903a3b..1c25fca25 100644
--- a/openlp/core/lib/imagemanager.py
+++ b/openlp/core/lib/imagemanager.py
@@ -236,7 +236,7 @@ class ImageManager(QtCore.QObject):
         """
         Return the ``QImage`` from the cache. If not present wait for the background thread to process it.
         """
-        log.debug('getImage %s' % path)
+        log.debug('getImage {path}'.format(path=path))
         image = self._cache[(path, source, width, height)]
         if image.image is None:
             self._conversion_queue.modify_priority(image, Priority.High)
@@ -256,7 +256,7 @@ class ImageManager(QtCore.QObject):
         """
         Returns the byte string for an image. If not present wait for the background thread to process it.
         """
-        log.debug('get_image_bytes %s' % path)
+        log.debug('get_image_bytes {path}'.format(path=path))
         image = self._cache[(path, source, width, height)]
         if image.image_bytes is None:
             self._conversion_queue.modify_priority(image, Priority.Urgent)
@@ -271,7 +271,7 @@ class ImageManager(QtCore.QObject):
         """
         Add image to cache if it is not already there.
         """
-        log.debug('add_image %s' % path)
+        log.debug('add_image {path}'.format(path=path))
         if not (path, source, width, height) in self._cache:
             image = Image(path, source, background, width, height)
             self._cache[(path, source, width, height)] = image
diff --git a/openlp/core/lib/mediamanageritem.py b/openlp/core/lib/mediamanageritem.py
index 5af90c1b7..358c82543 100644
--- a/openlp/core/lib/mediamanageritem.py
+++ b/openlp/core/lib/mediamanageritem.py
@@ -186,7 +186,7 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
         for action in toolbar_actions:
             if action[0] == StringContent.Preview:
                 self.toolbar.addSeparator()
-            self.toolbar.add_toolbar_action('%s%sAction' % (self.plugin.name, action[0]),
+            self.toolbar.add_toolbar_action('{name}{action}Action'.format(name=self.plugin.name, action=action[0]),
                                             text=self.plugin.get_string(action[1])['title'], icon=action[2],
                                             tooltip=self.plugin.get_string(action[1])['tooltip'],
                                             triggers=action[3])
@@ -200,7 +200,7 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
         self.list_view.setSpacing(1)
         self.list_view.setSelectionMode(QtWidgets.QAbstractItemView.ExtendedSelection)
         self.list_view.setAlternatingRowColors(True)
-        self.list_view.setObjectName('%sListView' % self.plugin.name)
+        self.list_view.setObjectName('{name}ListView'.format(name=self.plugin.name))
         # Add to page_layout
         self.page_layout.addWidget(self.list_view)
         # define and add the context menu
@@ -212,19 +212,22 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
                                  triggers=self.on_edit_click)
             create_widget_action(self.list_view, separator=True)
         create_widget_action(self.list_view,
-                             'listView%s%sItem' % (self.plugin.name.title(), StringContent.Preview.title()),
+                             'listView{plugin}{preview}Item'.format(plugin=self.plugin.name.title(),
+                                                                    preview=StringContent.Preview.title()),
                              text=self.plugin.get_string(StringContent.Preview)['title'],
                              icon=':/general/general_preview.png',
                              can_shortcuts=True,
                              triggers=self.on_preview_click)
         create_widget_action(self.list_view,
-                             'listView%s%sItem' % (self.plugin.name.title(), StringContent.Live.title()),
+                             'listView{plugin}{live}Item'.format(plugin=self.plugin.name.title(),
+                                                                 live=StringContent.Live.title()),
                              text=self.plugin.get_string(StringContent.Live)['title'],
                              icon=':/general/general_live.png',
                              can_shortcuts=True,
                              triggers=self.on_live_click)
         create_widget_action(self.list_view,
-                             'listView%s%sItem' % (self.plugin.name.title(), StringContent.Service.title()),
+                             'listView{plugin}{service}Item'.format(plugin=self.plugin.name.title(),
+                                                                    service=StringContent.Service.title()),
                              can_shortcuts=True,
                              text=self.plugin.get_string(StringContent.Service)['title'],
                              icon=':/general/general_add.png',
@@ -232,7 +235,8 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
         if self.has_delete_icon:
             create_widget_action(self.list_view, separator=True)
             create_widget_action(self.list_view,
-                                 'listView%s%sItem' % (self.plugin.name.title(), StringContent.Delete.title()),
+                                 'listView{plugin}{delete}Item'.format(plugin=self.plugin.name.title(),
+                                                                       delete=StringContent.Delete.title()),
                                  text=self.plugin.get_string(StringContent.Delete)['title'],
                                  icon=':/general/general_delete.png',
                                  can_shortcuts=True, triggers=self.on_delete_click)
@@ -313,7 +317,7 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
         files = FileDialog.getOpenFileNames(self, self.on_new_prompt,
                                             Settings().value(self.settings_section + '/last directory'),
                                             self.on_new_file_masks)
-        log.info('New files(s) %s' % files)
+        log.info('New files(s) {files}'.format(files=files))
         if files:
             self.application.set_busy_cursor()
             self.validate_and_load(files)
@@ -333,7 +337,8 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
                 if not error_shown:
                     critical_error_message_box(translate('OpenLP.MediaManagerItem', 'Invalid File Type'),
                                                translate('OpenLP.MediaManagerItem',
-                                                         'Invalid File %s.\nSuffix not supported') % file_name)
+                                                         'Invalid File {name}.\n'
+                                                         'Suffix not supported').format(name=file_name))
                     error_shown = True
             else:
                 new_files.append(file_name)
@@ -375,7 +380,8 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
             self.load_list(full_list, target_group)
             last_dir = os.path.split(files[0])[0]
             Settings().setValue(self.settings_section + '/last directory', last_dir)
-            Settings().setValue('%s/%s files' % (self.settings_section, self.settings_section), self.get_file_list())
+            Settings().setValue('{section}/{section} files'.format(section=self.settings_section),
+                                self.get_file_list())
         if duplicates_found:
             critical_error_message_box(UiStrings().Duplicate,
                                        translate('OpenLP.MediaManagerItem',
@@ -550,7 +556,7 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
             # Is it possible to process multiple list items to generate
             # multiple service items?
             if self.single_service_item:
-                log.debug('%s Add requested', self.plugin.name)
+                log.debug('{plugin} Add requested'.format(plugin=self.plugin.name))
                 self.add_to_service(replace=self.remote_triggered)
             else:
                 items = self.list_view.selectedIndexes()
@@ -591,7 +597,7 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
                                               translate('OpenLP.MediaManagerItem',
                                                         'You must select one or more items.'))
         else:
-            log.debug('%s Add requested', self.plugin.name)
+            log.debug('{plugin} Add requested'.format(plugin=self.plugin.name))
             service_item = self.service_manager.get_service_item()
             if not service_item:
                 QtWidgets.QMessageBox.information(self, UiStrings().NISs,
@@ -604,7 +610,8 @@ class MediaManagerItem(QtWidgets.QWidget, RegistryProperties):
                 # Turn off the remote edit update message indicator
                 QtWidgets.QMessageBox.information(self, translate('OpenLP.MediaManagerItem', 'Invalid Service Item'),
                                                   translate('OpenLP.MediaManagerItem',
-                                                            'You must select a %s service item.') % self.title)
+                                                            'You must select a {title} '
+                                                            'service item.').format(title=self.title))
 
     def build_service_item(self, item=None, xml_version=False, remote=False, context=ServiceItemContext.Live):
         """
diff --git a/openlp/core/lib/plugin.py b/openlp/core/lib/plugin.py
index b9c8ca5f0..9df77760b 100644
--- a/openlp/core/lib/plugin.py
+++ b/openlp/core/lib/plugin.py
@@ -130,7 +130,7 @@ class Plugin(QtCore.QObject, RegistryProperties):
         :param settings_tab_class: The class name of the plugin's settings tab.
         :param version: Defaults to *None*, which means that the same version number is used as OpenLP's version number.
         """
-        log.debug('Plugin %s initialised' % name)
+        log.debug('Plugin {plugin} initialised'.format(plugin=name))
         super(Plugin, self).__init__()
         self.name = name
         self.text_strings = {}
@@ -154,11 +154,11 @@ class Plugin(QtCore.QObject, RegistryProperties):
         # Append a setting for files in the mediamanager (note not all plugins
         # which have a mediamanager need this).
         if media_item_class is not None:
-            default_settings['%s/%s files' % (name, name)] = []
+            default_settings['{name}/{name} files'.format(name=name)] = []
         # Add settings to the dict of all settings.
         Settings.extend_default_settings(default_settings)
-        Registry().register_function('%s_add_service_item' % self.name, self.process_add_service_event)
-        Registry().register_function('%s_config_updated' % self.name, self.config_update)
+        Registry().register_function('{name}_add_service_item'.format(name=self.name), self.process_add_service_event)
+        Registry().register_function('{name}_config_updated'.format(name=self.name), self.config_update)
 
     def check_pre_conditions(self):
         """
@@ -256,7 +256,7 @@ class Plugin(QtCore.QObject, RegistryProperties):
         """
         Generic Drag and drop handler triggered from service_manager.
         """
-        log.debug('process_add_service_event event called for plugin %s' % self.name)
+        log.debug('process_add_service_event event called for plugin {name}'.format(name=self.name))
         if replace:
             self.media_item.on_add_edit_click()
         else:
diff --git a/openlp/core/lib/pluginmanager.py b/openlp/core/lib/pluginmanager.py
index 598c7c5d1..4eb4c2f01 100644
--- a/openlp/core/lib/pluginmanager.py
+++ b/openlp/core/lib/pluginmanager.py
@@ -43,7 +43,7 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
         super(PluginManager, self).__init__(parent)
         self.log_info('Plugin manager Initialising')
         self.base_path = os.path.abspath(AppLocation.get_directory(AppLocation.PluginsDir))
-        self.log_debug('Base path %s ' % self.base_path)
+        self.log_debug('Base path {path}'.format(path=self.base_path))
         self.plugins = []
         self.log_info('Plugin manager Initialised')
 
@@ -73,7 +73,7 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
         """
         start_depth = len(os.path.abspath(self.base_path).split(os.sep))
         present_plugin_dir = os.path.join(self.base_path, 'presentations')
-        self.log_debug('finding plugins in %s at depth %d' % (self.base_path, start_depth))
+        self.log_debug('finding plugins in {path} at depth {depth:d}'.format(path=self.base_path, depth=start_depth))
         for root, dirs, files in os.walk(self.base_path):
             for name in files:
                 if name.endswith('.py') and not name.startswith('__'):
@@ -84,7 +84,9 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
                         break
                     module_name = name[:-3]
                     # import the modules
-                    self.log_debug('Importing %s from %s. Depth %d' % (module_name, root, this_depth))
+                    self.log_debug('Importing {name} from {root}. Depth {depth:d}'.format(name=module_name,
+                                                                                          root=root,
+                                                                                          depth=this_depth))
                     try:
                         # Use the "imp" library to try to get around a problem with the PyUNO library which
                         # monkey-patches the __import__ function to do some magic. This causes issues with our tests.
@@ -93,21 +95,21 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
                         # Then load the module (do the actual import) using the details from find_module()
                         imp.load_module(module_name, fp, path_name, description)
                     except ImportError as e:
-                        self.log_exception('Failed to import module %s on path %s: %s'
-                                           % (module_name, path, e.args[0]))
+                        self.log_exception('Failed to import module {name} on path {path}: '
+                                           '{args}'.format(name=module_name, path=path, args=e.args[0]))
         plugin_classes = Plugin.__subclasses__()
         plugin_objects = []
         for p in plugin_classes:
             try:
                 plugin = p()
-                self.log_debug('Loaded plugin %s' % str(p))
+                self.log_debug('Loaded plugin {plugin}'.format(plugin=str(p)))
                 plugin_objects.append(plugin)
             except TypeError:
-                self.log_exception('Failed to load plugin %s' % str(p))
+                self.log_exception('Failed to load plugin {plugin}'.format(plugin=str(p)))
         plugins_list = sorted(plugin_objects, key=lambda plugin: plugin.weight)
         for plugin in plugins_list:
             if plugin.check_pre_conditions():
-                self.log_debug('Plugin %s active' % str(plugin.name))
+                self.log_debug('Plugin {plugin} active'.format(plugin=str(plugin.name)))
                 plugin.set_status()
             else:
                 plugin.status = PluginStatus.Disabled
@@ -175,10 +177,11 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
         Loop through all the plugins and give them an opportunity to initialise themselves.
         """
         for plugin in self.plugins:
-            self.log_info('initialising plugins %s in a %s state' % (plugin.name, plugin.is_active()))
+            self.log_info('initialising plugins {plugin} in a {state} state'.format(plugin=plugin.name,
+                                                                                    state=plugin.is_active()))
             if plugin.is_active():
                 plugin.initialise()
-                self.log_info('Initialisation Complete for %s ' % plugin.name)
+                self.log_info('Initialisation Complete for {plugin}'.format(plugin=plugin.name))
 
     def finalise_plugins(self):
         """
@@ -187,7 +190,7 @@ class PluginManager(RegistryMixin, OpenLPMixin, RegistryProperties):
         for plugin in self.plugins:
             if plugin.is_active():
                 plugin.finalise()
-                self.log_info('Finalisation Complete for %s ' % plugin.name)
+                self.log_info('Finalisation Complete for {plugin}'.format(plugin=plugin.name))
 
     def get_plugin_by_name(self, name):
         """
diff --git a/openlp/core/lib/renderer.py b/openlp/core/lib/renderer.py
index f76d28853..0d233a9c4 100644
--- a/openlp/core/lib/renderer.py
+++ b/openlp/core/lib/renderer.py
@@ -107,7 +107,7 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
 
         :param theme_name: The theme name
         """
-        self.log_debug("_set_theme with theme %s" % theme_name)
+        self.log_debug("_set_theme with theme {theme}".format(theme=theme_name))
         if theme_name not in self._theme_dimensions:
             theme_data = self.theme_manager.get_theme_data(theme_name)
             main_rect = self.get_main_rectangle(theme_data)
@@ -183,7 +183,7 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
 
         :param item_theme_name: The item theme's name.
         """
-        self.log_debug("set_item_theme with theme %s" % item_theme_name)
+        self.log_debug("set_item_theme with theme {theme}".format(theme=item_theme_name))
         self._set_theme(item_theme_name)
         self.item_theme_name = item_theme_name
 
@@ -317,7 +317,7 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
         self.width = screen_size.width()
         self.height = screen_size.height()
         self.screen_ratio = self.height / self.width
-        self.log_debug('_calculate default %s, %f' % (screen_size, self.screen_ratio))
+        self.log_debug('_calculate default {size}, {ratio:f}'.format(size=screen_size, ratio=self.screen_ratio))
         # 90% is start of footer
         self.footer_start = int(self.height * 0.90)
 
@@ -354,7 +354,7 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
         :param rect_main: The main text block.
         :param rect_footer: The footer text block.
         """
-        self.log_debug('_set_text_rectangle %s , %s' % (rect_main, rect_footer))
+        self.log_debug('_set_text_rectangle {main} , {footer}'.format(main=rect_main, footer=rect_footer))
         self._rect = rect_main
         self._rect_footer = rect_footer
         self.page_width = self._rect.width()
@@ -370,6 +370,7 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
         self.web.resize(self.page_width, self.page_height)
         self.web_frame = self.web.page().mainFrame()
         # Adjust width and height to account for shadow. outline done in css.
+        # TODO: Verify before converting to python3 strings
         html = """<!DOCTYPE html><html><head><script>
             function show_text(newtext) {
                 var main = document.getElementById('main');
@@ -518,7 +519,8 @@ class Renderer(OpenLPMixin, RegistryMixin, RegistryProperties):
 
         :param text:  The text to check. It may contain HTML tags.
         """
-        self.web_frame.evaluateJavaScript('show_text("%s")' % text.replace('\\', '\\\\').replace('\"', '\\\"'))
+        self.web_frame.evaluateJavaScript('show_text'
+                                          '("{text}")'.format(text=text.replace('\\', '\\\\').replace('\"', '\\\"')))
         return self.web_frame.contentsSize().height() <= self.empty_height
 
 
diff --git a/openlp/core/lib/screen.py b/openlp/core/lib/screen.py
index 819ba9763..e7b4c0b97 100644
--- a/openlp/core/lib/screen.py
+++ b/openlp/core/lib/screen.py
@@ -78,7 +78,7 @@ class ScreenList(object):
         ``number``
             The number of the screen, which size has changed.
         """
-        log.info('screen_resolution_changed %d' % number)
+        log.info('screen_resolution_changed {number:d}'.format(number=number))
         for screen in self.screen_list:
             if number == screen['number']:
                 new_screen = {
@@ -105,7 +105,7 @@ class ScreenList(object):
         """
         # Do not log at start up.
         if changed_screen != -1:
-            log.info('screen_count_changed %d' % self.desktop.screenCount())
+            log.info('screen_count_changed {count:d}'.format(count=self.desktop.screenCount()))
         # Remove unplugged screens.
         for screen in copy.deepcopy(self.screen_list):
             if screen['number'] == self.desktop.screenCount():
@@ -132,9 +132,11 @@ class ScreenList(object):
         """
         screen_list = []
         for screen in self.screen_list:
-            screen_name = '%s %d' % (translate('OpenLP.ScreenList', 'Screen'), screen['number'] + 1)
+            screen_name = '{name} {number:d}'.format(name=translate('OpenLP.ScreenList', 'Screen'),
+                                                     number=screen['number'] + 1)
             if screen['primary']:
-                screen_name = '%s (%s)' % (screen_name, translate('OpenLP.ScreenList', 'primary'))
+                screen_name = '{name} ({primary})'.format(name=screen_name,
+                                                          primary=translate('OpenLP.ScreenList', 'primary'))
             screen_list.append(screen_name)
         return screen_list
 
@@ -152,7 +154,7 @@ class ScreenList(object):
                     'size': PyQt5.QtCore.QRect(0, 0, 1024, 768)
                 }
         """
-        log.info('Screen %d found with resolution %s' % (screen['number'], screen['size']))
+        log.info('Screen {number:d} found with resolution {size}'.format(number=screen['number'], size=screen['size']))
         if screen['primary']:
             self.current = screen
             self.override = copy.deepcopy(self.current)
@@ -165,7 +167,7 @@ class ScreenList(object):
 
         :param number: The screen number (int).
         """
-        log.info('remove_screen %d' % number)
+        log.info('remove_screen {number:d}'.forma(number=number))
         for screen in self.screen_list:
             if screen['number'] == number:
                 self.screen_list.remove(screen)
@@ -189,7 +191,7 @@ class ScreenList(object):
 
         :param number: The screen number (int).
         """
-        log.debug('set_current_display %s' % number)
+        log.debug('set_current_display {number}'.format(number=number))
         if number + 1 > self.display_count:
             self.current = self.screen_list[0]
         else:
diff --git a/openlp/core/lib/searchedit.py b/openlp/core/lib/searchedit.py
index 0cdeb271a..41e54957d 100644
--- a/openlp/core/lib/searchedit.py
+++ b/openlp/core/lib/searchedit.py
@@ -62,9 +62,10 @@ class SearchEdit(QtWidgets.QLineEdit):
         right_padding = self.clear_button.width() + frame_width
         if hasattr(self, 'menu_button'):
             left_padding = self.menu_button.width()
-            stylesheet = 'QLineEdit { padding-left: %spx; padding-right: %spx; } ' % (left_padding, right_padding)
+            stylesheet = 'QLineEdit {{ padding-left:{left}px; padding-right: {right}px; }} '.format(left=left_padding,
+                                                                                                    right=right_padding)
         else:
-            stylesheet = 'QLineEdit { padding-right: %spx; } ' % right_padding
+            stylesheet = 'QLineEdit {{ padding-right: {right}px; }} '.format(right=right_padding)
         self.setStyleSheet(stylesheet)
         msz = self.minimumSizeHint()
         self.setMinimumSize(max(msz.width(), self.clear_button.width() + (frame_width * 2) + 2),
diff --git a/openlp/core/lib/serviceitem.py b/openlp/core/lib/serviceitem.py
index 2cbbb98e9..c0a819390 100644
--- a/openlp/core/lib/serviceitem.py
+++ b/openlp/core/lib/serviceitem.py
@@ -247,7 +247,7 @@ class ServiceItem(RegistryProperties):
             self.renderer.set_item_theme(self.theme)
             self.theme_data, self.main, self.footer = self.renderer.pre_render()
         if self.service_item_type == ServiceItemType.Text:
-            log.debug('Formatting slides: %s' % self.title)
+            log.debug('Formatting slides: {title}'.format(title=self.title))
             # Save rendered pages to this dict. In the case that a slide is used twice we can use the pages saved to
             # the dict instead of rendering them again.
             previous_pages = {}
@@ -270,7 +270,7 @@ class ServiceItem(RegistryProperties):
         elif self.service_item_type == ServiceItemType.Image or self.service_item_type == ServiceItemType.Command:
             pass
         else:
-            log.error('Invalid value renderer: %s' % self.service_item_type)
+            log.error('Invalid value renderer: {item}'.format(item=self.service_item_type))
         self.title = clean_tags(self.title)
         # The footer should never be None, but to be compatible with a few
         # nightly builds between 1.9.4 and 1.9.5, we have to correct this to
@@ -325,7 +325,8 @@ class ServiceItem(RegistryProperties):
         self.service_item_type = ServiceItemType.Command
         # If the item should have a display title but this frame doesn't have one, we make one up
         if self.is_capable(ItemCapabilities.HasDisplayTitle) and not display_title:
-            display_title = translate('OpenLP.ServiceItem', '[slide %d]') % (len(self._raw_frames) + 1)
+            display_title = translate('OpenLP.ServiceItem',
+                                      '[slide {frame:d}]').format(frame=len(self._raw_frames) + 1)
         # Update image path to match servicemanager location if file was loaded from service
         if image and not self.has_original_files and self.name == 'presentations':
             file_location = os.path.join(path, file_name)
@@ -392,7 +393,7 @@ class ServiceItem(RegistryProperties):
         :param path: Defaults to *None*. This is the service manager path for things which have their files saved
             with them or None when the saved service is lite and the original file paths need to be preserved.
         """
-        log.debug('set_from_service called with path %s' % path)
+        log.debug('set_from_service called with path {path}'.format(path=path))
         header = service_item['serviceitem']['header']
         self.title = header['title']
         self.name = header['name']
@@ -608,11 +609,13 @@ class ServiceItem(RegistryProperties):
         start = None
         end = None
         if self.start_time != 0:
-            start = translate('OpenLP.ServiceItem', '<strong>Start</strong>: %s') % \
-                str(datetime.timedelta(seconds=self.start_time))
+            time = str(datetime.timedelta(seconds=self.start_time))
+            start = translate('OpenLP.ServiceItem',
+                              '<strong>Start</strong>: {start}').format(start=time)
         if self.media_length != 0:
-            end = translate('OpenLP.ServiceItem', '<strong>Length</strong>: %s') % \
-                str(datetime.timedelta(seconds=self.media_length // 1000))
+            length = str(datetime.timedelta(seconds=self.media_length // 1000))
+            end = translate('OpenLP.ServiceItem', '<strong>Length</strong>: {length}').format(length=length)
+
         if not start and not end:
             return ''
         elif start and not end:
@@ -620,7 +623,7 @@ class ServiceItem(RegistryProperties):
         elif not start and end:
             return end
         else:
-            return '%s <br>%s' % (start, end)
+            return '{start} <br>{end}'.format(start=start, end=end)
 
     def update_theme(self, theme):
         """
diff --git a/openlp/core/lib/theme.py b/openlp/core/lib/theme.py
index bd35c4bdb..4e84d353b 100644
--- a/openlp/core/lib/theme.py
+++ b/openlp/core/lib/theme.py
@@ -427,7 +427,7 @@ class ThemeXML(object):
         try:
             theme_xml = objectify.fromstring(xml)
         except etree.XMLSyntaxError:
-            log.exception('Invalid xml %s', xml)
+            log.exception('Invalid xml {text}'.format(text=xml))
             return
         xml_iter = theme_xml.getiterator()
         for element in xml_iter:
@@ -513,6 +513,7 @@ class ThemeXML(object):
         theme_strings = []
         for key in dir(self):
             if key[0:1] != '_':
+                # TODO: Verify spacing format before converting to python3 string
                 theme_strings.append('%30s: %s' % (key, getattr(self, key)))
         return '\n'.join(theme_strings)
 
diff --git a/openlp/core/lib/ui.py b/openlp/core/lib/ui.py
index ab47a65e1..d36512d1a 100644
--- a/openlp/core/lib/ui.py
+++ b/openlp/core/lib/ui.py
@@ -165,7 +165,7 @@ def create_button(parent, name, **kwargs):
             kwargs.setdefault('icon', ':/services/service_down.png')
             kwargs.setdefault('tooltip', translate('OpenLP.Ui', 'Move selection down one position.'))
         else:
-            log.warning('The role "%s" is not defined in create_push_button().', role)
+            log.warning('The role "{role}" is not defined in create_push_button().'.format(role=role))
     if kwargs.pop('btn_class', '') == 'toolbutton':
         button = QtWidgets.QToolButton(parent)
     else:
@@ -183,7 +183,7 @@ def create_button(parent, name, **kwargs):
         button.clicked.connect(kwargs.pop('click'))
     for key in list(kwargs.keys()):
         if key not in ['text', 'icon', 'tooltip', 'click']:
-            log.warning('Parameter %s was not consumed in create_button().', key)
+            log.warning('Parameter {key} was not consumed in create_button().'.format(key=key))
     return button
 
 
@@ -270,7 +270,7 @@ def create_action(parent, name, **kwargs):
         action.triggered.connect(kwargs.pop('triggers'))
     for key in list(kwargs.keys()):
         if key not in ['text', 'icon', 'tooltip', 'statustip', 'checked', 'can_shortcuts', 'category', 'triggers']:
-            log.warning('Parameter %s was not consumed in create_action().' % key)
+            log.warning('Parameter {key} was not consumed in create_action().'.format(key=key))
     return action
 
 
diff --git a/openlp/core/lib/webpagereader.py b/openlp/core/lib/webpagereader.py
index 653717c93..260ef1556 100644
--- a/openlp/core/lib/webpagereader.py
+++ b/openlp/core/lib/webpagereader.py
@@ -133,37 +133,37 @@ def get_web_page(url, header=None, update_openlp=False):
         time.sleep(0.1)
         try:
             page = urllib.request.urlopen(req, timeout=CONNECTION_TIMEOUT)
-            log.debug('Downloaded page {}'.format(page.geturl()))
+            log.debug('Downloaded page {text}'.format(text=page.geturl()))
             break
         except urllib.error.URLError as err:
-            log.exception('URLError on {}'.format(url))
-            log.exception('URLError: {}'.format(err.reason))
+            log.exception('URLError on {text}'.format(text=url))
+            log.exception('URLError: {text}'.format(text=err.reason))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
         except socket.timeout:
-            log.exception('Socket timeout: {}'.format(url))
+            log.exception('Socket timeout: {text}'.format(text=url))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
         except socket.gaierror:
-            log.exception('Socket gaierror: {}'.format(url))
+            log.exception('Socket gaierror: {text}'.format(text=url))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
         except ConnectionRefusedError:
-            log.exception('ConnectionRefused: {}'.format(url))
+            log.exception('ConnectionRefused: {text}'.format(text=url))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
             break
         except ConnectionError:
-            log.exception('Connection error: {}'.format(url))
+            log.exception('Connection error: {text}'.format(text=url))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
         except HTTPException:
-            log.exception('HTTPException error: {}'.format(url))
+            log.exception('HTTPException error: {text}'.format(text=url))
             page = None
             if retries > CONNECTION_RETRIES:
                 raise
@@ -173,7 +173,7 @@ def get_web_page(url, header=None, update_openlp=False):
     if update_openlp:
         Registry().get('application').process_events()
     if not page:
-        log.exception('{} could not be downloaded'.format(url))
+        log.exception('{text} could not be downloaded'.format(text=url))
         return None
     log.debug(page)
     return page
diff --git a/tests/functional/openlp_core_lib/test_projector_pjlink1.py b/tests/functional/openlp_core_lib/test_projector_pjlink1.py
index 4f81b2660..6c2f3c1d5 100644
--- a/tests/functional/openlp_core_lib/test_projector_pjlink1.py
+++ b/tests/functional/openlp_core_lib/test_projector_pjlink1.py
@@ -112,7 +112,7 @@ class TestPJLink(TestCase):
     @patch.object(pjlink_test, 'projectorReceivedData')
     def projector_process_lamp_test(self, mock_projectorReceivedData):
         """
-        Test setting lamp on/off and hours
+        Test status lamp on/off and hours
         """
         # GIVEN: Test object
         pjlink = pjlink_test
@@ -129,7 +129,7 @@ class TestPJLink(TestCase):
     @patch.object(pjlink_test, 'projectorReceivedData')
     def projector_process_multiple_lamp_test(self, mock_projectorReceivedData):
         """
-        Test setting multiple lamp on/off and hours
+        Test status multiple lamp on/off and hours
         """
         # GIVEN: Test object
         pjlink = pjlink_test
@@ -156,7 +156,7 @@ class TestPJLink(TestCase):
     @patch.object(pjlink_test, 'projectorReceivedData')
     def projector_process_power_on_test(self, mock_projectorReceivedData):
         """
-        Test setting power to ON
+        Test status power to ON
         """
         # GIVEN: Test object and preset
         pjlink = pjlink_test
@@ -171,7 +171,7 @@ class TestPJLink(TestCase):
     @patch.object(pjlink_test, 'projectorReceivedData')
     def projector_process_power_off_test(self, mock_projectorReceivedData):
         """
-        Test setting power to STANDBY
+        Test status power to STANDBY
         """
         # GIVEN: Test object and preset
         pjlink = pjlink_test
@@ -182,3 +182,71 @@ class TestPJLink(TestCase):
 
         # THEN: Power should be set to STANDBY
         self.assertEquals(pjlink.power, S_STANDBY, 'Power should have been set to STANDBY')
+
+    @patch.object(pjlink_test, 'projectorUpdateIcons')
+    def projector_process_avmt_closed_unmuted_test(self, mock_projectorReceivedData):
+        """
+        Test avmt status shutter closed and audio muted
+        """
+        # GIVEN: Test object
+        pjlink = pjlink_test
+        pjlink.shutter = False
+        pjlink.mute = True
+
+        # WHEN: Called with setting shutter closed and mute off
+        pjlink.process_avmt('11')
+
+        # THEN: Shutter should be True and mute should be False
+        self.assertTrue(pjlink.shutter, 'Shutter should have been set to closed')
+        self.assertFalse(pjlink.mute, 'Audio should be off')
+
+    @patch.object(pjlink_test, 'projectorUpdateIcons')
+    def projector_process_avmt_open_muted_test(self, mock_projectorReceivedData):
+        """
+        Test avmt status shutter open and mute on
+        """
+        # GIVEN: Test object
+        pjlink = pjlink_test
+        pjlink.shutter = True
+        pjlink.mute = False
+
+        # WHEN: Called with setting shutter closed and mute on
+        pjlink.process_avmt('21')
+
+        # THEN: Shutter should be closed and mute should be True
+        self.assertFalse(pjlink.shutter, 'Shutter should have been set to closed')
+        self.assertTrue(pjlink.mute, 'Audio should be off')
+
+    @patch.object(pjlink_test, 'projectorUpdateIcons')
+    def projector_process_avmt_open_unmuted_test(self, mock_projectorReceivedData):
+        """
+        Test avmt status shutter open and mute off off
+        """
+        # GIVEN: Test object
+        pjlink = pjlink_test
+        pjlink.shutter = True
+        pjlink.mute = True
+
+        # WHEN: Called with setting shutter to closed and mute on
+        pjlink.process_avmt('30')
+
+        # THEN: Shutter should be closed and mute should be True
+        self.assertFalse(pjlink.shutter, 'Shutter should have been set to open')
+        self.assertFalse(pjlink.mute, 'Audio should be on')
+
+    @patch.object(pjlink_test, 'projectorUpdateIcons')
+    def projector_process_avmt_closed_muted_test(self, mock_projectorReceivedData):
+        """
+        Test avmt status shutter closed and mute off
+        """
+        # GIVEN: Test object
+        pjlink = pjlink_test
+        pjlink.shutter = False
+        pjlink.mute = False
+
+        # WHEN: Called with setting shutter to closed and mute on
+        pjlink.process_avmt('31')
+
+        # THEN: Shutter should be closed and mute should be True
+        self.assertTrue(pjlink.shutter, 'Shutter should have been set to closed')
+        self.assertTrue(pjlink.mute, 'Audio should be on')