diff --git a/mkdocs/commands/build.py b/mkdocs/commands/build.py
index 1fd31826..144c6230 100644
--- a/mkdocs/commands/build.py
+++ b/mkdocs/commands/build.py
@@ -136,7 +136,7 @@ def _build_extra_template(template_name, files, config, nav):
         return
 
     try:
-        with open(file.abs_src_path, 'r', encoding='utf-8', errors='strict') as f:
+        with open(file.abs_src_path, encoding='utf-8', errors='strict') as f:
             template = jinja2.Template(f.read())
     except Exception as e:
         log.warning(f"Error reading template '{template_name}': {e}")
diff --git a/mkdocs/commands/gh_deploy.py b/mkdocs/commands/gh_deploy.py
index 59f81e2d..b6b80fb4 100644
--- a/mkdocs/commands/gh_deploy.py
+++ b/mkdocs/commands/gh_deploy.py
@@ -116,14 +116,14 @@ def gh_deploy(config, message=None, force=False, ignore_version=False, shell=Fal
             nojekyll=True
         )
     except ghp_import.GhpError as e:
-        log.error("Failed to deploy to GitHub with error: \n{}".format(e.message))
+        log.error(f"Failed to deploy to GitHub with error: \n{e.message}")
         raise Abort('Deployment Aborted!')
 
     cname_file = os.path.join(config['site_dir'], 'CNAME')
     # Does this repository have a CNAME set for GitHub pages?
     if os.path.isfile(cname_file):
         # This GitHub pages repository has a CNAME configured.
-        with(open(cname_file, 'r')) as f:
+        with open(cname_file) as f:
             cname_host = f.read().strip()
         log.info(f'Based on your CNAME file, your documentation should be '
                  f'available shortly at: http://{cname_host}')
diff --git a/mkdocs/config/base.py b/mkdocs/config/base.py
index f06e3c03..8f7f8bef 100644
--- a/mkdocs/config/base.py
+++ b/mkdocs/config/base.py
@@ -126,7 +126,7 @@ class Config(UserDict):
             raise exceptions.ConfigurationError(
                 "The configuration is invalid. The expected type was a key "
                 "value mapping (a python dict) but we got an object of type: "
-                "{}".format(type(patch)))
+                f"{type(patch)}")
 
         self.user_configs.append(patch)
         self.data.update(patch)
@@ -234,11 +234,11 @@ def load_config(config_file=None, **kwargs):
 
     if len(errors) > 0:
         raise exceptions.Abort(
-            "Aborted with {} Configuration Errors!".format(len(errors))
+            f"Aborted with {len(errors)} Configuration Errors!"
         )
     elif cfg['strict'] and len(warnings) > 0:
         raise exceptions.Abort(
-            "Aborted with {} Configuration Warnings in 'strict' mode!".format(len(warnings))
+            f"Aborted with {len(warnings)} Configuration Warnings in 'strict' mode!"
         )
 
     return cfg
diff --git a/mkdocs/config/config_options.py b/mkdocs/config/config_options.py
index 025fd5a6..374d9619 100644
--- a/mkdocs/config/config_options.py
+++ b/mkdocs/config/config_options.py
@@ -147,9 +147,8 @@ class Type(OptionallyRequired):
         if not isinstance(value, self._type):
             msg = f"Expected type: {self._type} but received: {type(value)}"
         elif self.length is not None and len(value) != self.length:
-            msg = ("Expected type: {0} with length {2} but received: {1} with "
-                   "length {3}").format(self._type, value, self.length,
-                                        len(value))
+            msg = (f"Expected type: {self._type} with length {self.length}"
+                   f" but received: {value} with length {len(value)}")
         else:
             return value
 
@@ -274,10 +273,10 @@ class IpAddress(OptionallyRequired):
         host = config[key_name].host
         if key_name == 'dev_addr' and host in ['0.0.0.0', '::']:
             self.warnings.append(
-                ("The use of the IP address '{}' suggests a production environment "
+                (f"The use of the IP address '{host}' suggests a production environment "
                  "or the use of a proxy to connect to the MkDocs server. However, "
                  "the MkDocs' server is intended for local development purposes only. "
-                 "Please use a third party production-ready server instead.").format(host)
+                 "Please use a third party production-ready server instead.")
             )
 
 
@@ -392,9 +391,9 @@ class Dir(FilesystemObject):
         # Validate that the dir is not the parent dir of the config file.
         if os.path.dirname(config.config_file_path) == config[key_name]:
             raise ValidationError(
-                ("The '{0}' should not be the parent directory of the config "
-                 "file. Use a child directory instead so that the '{0}' "
-                 "is a sibling of the config file.").format(key_name))
+                (f"The '{key_name}' should not be the parent directory of the"
+                 " config file. Use a child directory instead so that the"
+                 f" '{key_name}' is a sibling of the config file."))
 
 
 class File(FilesystemObject):
@@ -487,7 +486,7 @@ class Theme(BaseConfigOption):
                                   format(path=theme_config['custom_dir'], name=key_name))
 
         if 'locale' in theme_config and not isinstance(theme_config['locale'], str):
-            raise ValidationError("'{name}.locale' must be a string.".format(name=theme_config['name']))
+            raise ValidationError(f"'{theme_config['name']}.locale' must be a string.")
 
         config[key_name] = theme.Theme(**theme_config)
 
@@ -647,9 +646,9 @@ class Plugins(OptionallyRequired):
         Plugin = self.installed_plugins[name].load()
 
         if not issubclass(Plugin, plugins.BasePlugin):
-            raise ValidationError('{}.{} must be a subclass of {}.{}'.format(
-                Plugin.__module__, Plugin.__name__, plugins.BasePlugin.__module__,
-                plugins.BasePlugin.__name__))
+            raise ValidationError(
+                f'{Plugin.__module__}.{Plugin.__name__} must be a subclass of'
+                f' {plugins.BasePlugin.__module__}.{plugins.BasePlugin.__name__}')
 
         plugin = Plugin()
         errors, warnings = plugin.load_config(config, self.config_file_path)
diff --git a/mkdocs/plugins.py b/mkdocs/plugins.py
index 8cd60e2d..4cc978b9 100644
--- a/mkdocs/plugins.py
+++ b/mkdocs/plugins.py
@@ -76,9 +76,9 @@ class PluginCollection(OrderedDict):
     def __setitem__(self, key, value, **kwargs):
         if not isinstance(value, BasePlugin):
             raise TypeError(
-                '{}.{} only accepts values which are instances of {}.{} '
-                'sublcasses'.format(self.__module__, self.__name__,
-                                    BasePlugin.__module__, BasePlugin.__name__))
+                f'{self.__module__}.{self.__name__} only accepts values which'
+                f' are instances of {BasePlugin.__module__}.{BasePlugin.__name__}'
+                ' subclasses')
         super().__setitem__(key, value, **kwargs)
         # Register all of the event methods defined for this Plugin.
         for event_name in (x for x in dir(value) if x.startswith('on_')):
diff --git a/mkdocs/structure/files.py b/mkdocs/structure/files.py
index 26264625..e42c05fc 100644
--- a/mkdocs/structure/files.py
+++ b/mkdocs/structure/files.py
@@ -142,8 +142,9 @@ class File:
         return not self.__eq__(other)
 
     def __repr__(self):
-        return "File(src_path='{}', dest_path='{}', name='{}', url='{}')".format(
-            self.src_path, self.dest_path, self.name, self.url
+        return (
+            f"File(src_path='{self.src_path}', dest_path='{self.dest_path}',"
+            f" name='{self.name}', url='{self.url}')"
         )
 
     def _get_stem(self):
diff --git a/mkdocs/structure/nav.py b/mkdocs/structure/nav.py
index dac1beef..b8883773 100644
--- a/mkdocs/structure/nav.py
+++ b/mkdocs/structure/nav.py
@@ -127,18 +127,17 @@ def get_navigation(files, config):
         scheme, netloc, path, query, fragment = urlsplit(link.url)
         if scheme or netloc:
             log.debug(
-                "An external link to '{}' is included in "
-                "the 'nav' configuration.".format(link.url)
+                f"An external link to '{link.url}' is included in the 'nav' configuration."
             )
         elif link.url.startswith('/'):
             log.debug(
-                "An absolute path to '{}' is included in the 'nav' configuration, "
-                "which presumably points to an external resource.".format(link.url)
+                f"An absolute path to '{link.url}' is included in the 'nav' "
+                "configuration, which presumably points to an external resource."
             )
         else:
             msg = (
-                "A relative path to '{}' is included in the 'nav' configuration, "
-                "which is not found in the documentation files".format(link.url)
+                f"A relative path to '{link.url}' is included in the 'nav' "
+                "configuration, which is not found in the documentation files"
             )
             log.warning(msg)
     return Navigation(items, pages)
diff --git a/mkdocs/structure/pages.py b/mkdocs/structure/pages.py
index 76eede6a..b993ae24 100644
--- a/mkdocs/structure/pages.py
+++ b/mkdocs/structure/pages.py
@@ -54,7 +54,8 @@ class Page:
 
     def __repr__(self):
         title = f"'{self.title}'" if (self.title is not None) else '[blank]'
-        return "Page(title={}, url='{}')".format(title, self.abs_url or self.file.url)
+        url = self.abs_url or self.file.url
+        return f"Page(title={title}, url='{url}')"
 
     def _indent_print(self, depth=0):
         return '{}{}'.format('    ' * depth, repr(self))
@@ -116,7 +117,7 @@ class Page:
         )
         if source is None:
             try:
-                with open(self.file.abs_src_path, 'r', encoding='utf-8-sig', errors='strict') as f:
+                with open(self.file.abs_src_path, encoding='utf-8-sig', errors='strict') as f:
                     source = f.read()
             except OSError:
                 log.error(f'File not found: {self.file.src_path}')
diff --git a/mkdocs/tests/gh_deploy_tests.py b/mkdocs/tests/gh_deploy_tests.py
index f2301df8..f9fa5491 100644
--- a/mkdocs/tests/gh_deploy_tests.py
+++ b/mkdocs/tests/gh_deploy_tests.py
@@ -159,7 +159,7 @@ class TestGitHubDeployLogs(unittest.TestCase):
             gh_deploy._check_version('gh-pages')
         self.assertEqual(
             cm.output, ['INFO:mkdocs.commands.gh_deploy:Previous deployment was done with MkDocs '
-                        'version 0.1.2; you are deploying with a newer version ({})'.format(__version__)]
+                        f'version 0.1.2; you are deploying with a newer version ({__version__})']
         )
 
     @mock.patch('subprocess.Popen')
@@ -171,8 +171,8 @@ class TestGitHubDeployLogs(unittest.TestCase):
             self.assertRaises(Abort, gh_deploy._check_version, 'gh-pages')
         self.assertEqual(
             cm.output, ['ERROR:mkdocs.commands.gh_deploy:Deployment terminated: Previous deployment was made with '
-                        'MkDocs version 10.1.2; you are attempting to deploy with an older version ({}). Use '
-                        '--ignore-version to deploy anyway.'.format(__version__)]
+                        f'MkDocs version 10.1.2; you are attempting to deploy with an older version ({__version__}).'
+                        ' Use --ignore-version to deploy anyway.']
         )
 
     @mock.patch('subprocess.Popen')
diff --git a/mkdocs/tests/localization_tests.py b/mkdocs/tests/localization_tests.py
index 704c7989..a7ceff96 100644
--- a/mkdocs/tests/localization_tests.py
+++ b/mkdocs/tests/localization_tests.py
@@ -1,7 +1,5 @@
 #!/usr/bin/env python
-# coding: utf-8
 
-from __future__ import unicode_literals
 
 import unittest
 
diff --git a/mkdocs/tests/plugin_tests.py b/mkdocs/tests/plugin_tests.py
index 295a75d1..bc40a296 100644
--- a/mkdocs/tests/plugin_tests.py
+++ b/mkdocs/tests/plugin_tests.py
@@ -21,7 +21,7 @@ class DummyPlugin(plugins.BasePlugin):
 
     def on_pre_page(self, content, **kwargs):
         """ modify page content by prepending `foo` config value. """
-        return '{} {}'.format(self.config['foo'], content)
+        return f'{self.config["foo"]} {content}'
 
     def on_nav(self, item, **kwargs):
         """ do nothing (return None) to not modify item. """
@@ -29,7 +29,7 @@ class DummyPlugin(plugins.BasePlugin):
 
     def on_page_read_source(self, **kwargs):
         """ create new source by prepending `foo` config value to 'source'. """
-        return '{} {}'.format(self.config['foo'], 'source')
+        return f'{self.config["foo"]} source'
 
     def on_pre_build(self, **kwargs):
         """ do nothing (return None). """
diff --git a/mkdocs/tests/search_tests.py b/mkdocs/tests/search_tests.py
index 439faea7..c0cc0e1e 100644
--- a/mkdocs/tests/search_tests.py
+++ b/mkdocs/tests/search_tests.py
@@ -382,7 +382,7 @@ class SearchIndexTests(unittest.TestCase):
         """)
         toc = get_toc(get_markdown_toc(md))
 
-        full_content = ''.join("""Heading{0}Content{0}""".format(i) for i in range(1, 4))
+        full_content = ''.join(f"Heading{i}Content{i}" for i in range(1, 4))
 
         plugin = search.SearchPlugin()
         errors, warnings = plugin.load_config({})
diff --git a/mkdocs/tests/structure/file_tests.py b/mkdocs/tests/structure/file_tests.py
index b1b399a0..6ecc2587 100644
--- a/mkdocs/tests/structure/file_tests.py
+++ b/mkdocs/tests/structure/file_tests.py
@@ -650,7 +650,7 @@ class TestFiles(PathAssertionMixin, unittest.TestCase):
         dest_path = os.path.join(dest_dir, 'test.txt')
         file.copy_file(dirty=False)
         self.assertPathIsFile(dest_path)
-        with open(dest_path, 'r', encoding='utf-8') as f:
+        with open(dest_path, encoding='utf-8') as f:
             self.assertEqual(f.read(), 'source content')
 
     @tempdir(files={'test.txt': 'destination content'})
@@ -661,7 +661,7 @@ class TestFiles(PathAssertionMixin, unittest.TestCase):
         dest_path = os.path.join(dest_dir, 'test.txt')
         file.copy_file(dirty=True)
         self.assertPathIsFile(dest_path)
-        with open(dest_path, 'r', encoding='utf-8') as f:
+        with open(dest_path, encoding='utf-8') as f:
             self.assertEqual(f.read(), 'source content')
 
     @tempdir(files={'test.txt': 'destination content'})
@@ -672,7 +672,7 @@ class TestFiles(PathAssertionMixin, unittest.TestCase):
         dest_path = os.path.join(dest_dir, 'test.txt')
         file.copy_file(dirty=True)
         self.assertPathIsFile(dest_path)
-        with open(dest_path, 'r', encoding='utf-8') as f:
+        with open(dest_path, encoding='utf-8') as f:
             self.assertEqual(f.read(), 'destination content')
 
     def test_files_append_remove_src_paths(self):
diff --git a/setup.py b/setup.py
index b9834e51..e913eb1e 100755
--- a/setup.py
+++ b/setup.py
@@ -40,7 +40,8 @@ if sys.argv[-1] == 'publish':
     os.system("python setup.py sdist bdist_wheel")
     os.system("twine upload dist/*")
     print("You probably want to also tag the version now:")
-    print("  git tag -a {0} -m 'version {0}'".format(get_version("mkdocs")))
+    version = get_version("mkdocs")
+    print(f"  git tag -a {version} -m 'version {version}'")
     print("  git push --tags")
     sys.exit()