diff --git a/changelog.d/10197.misc b/changelog.d/10197.misc
new file mode 100644
index 000000000000..cbb3b454be15
--- /dev/null
+++ b/changelog.d/10197.misc
@@ -0,0 +1 @@
+Upgrade `black` linting tool to 21.6b0.
diff --git a/contrib/experiments/cursesio.py b/contrib/experiments/cursesio.py
index cff73650e6fe..7695cc77ca94 100644
--- a/contrib/experiments/cursesio.py
+++ b/contrib/experiments/cursesio.py
@@ -46,14 +46,14 @@ def set_callback(self, callback):
         self.callback = callback
 
     def fileno(self):
-        """ We want to select on FD 0 """
+        """We want to select on FD 0"""
         return 0
 
     def connectionLost(self, reason):
         self.close()
 
     def print_line(self, text):
-        """ add a line to the internal list of lines"""
+        """add a line to the internal list of lines"""
 
         self.lines.append(text)
         self.redraw()
@@ -92,7 +92,7 @@ def printLogLine(self, text):
         )
 
     def doRead(self):
-        """ Input is ready! """
+        """Input is ready!"""
         curses.noecho()
         c = self.stdscr.getch()  # read a character
 
@@ -132,7 +132,7 @@ def logPrefix(self):
         return "CursesStdIO"
 
     def close(self):
-        """ clean up """
+        """clean up"""
 
         curses.nocbreak()
         self.stdscr.keypad(0)
diff --git a/setup.py b/setup.py
index e2e488761dbf..1081548e0067 100755
--- a/setup.py
+++ b/setup.py
@@ -97,7 +97,7 @@ def exec_file(path_segments):
 # We pin black so that our tests don't start failing on new releases.
 CONDITIONAL_REQUIREMENTS["lint"] = [
     "isort==5.7.0",
-    "black==20.8b1",
+    "black==21.6b0",
     "flake8-comprehensions",
     "flake8-bugbear==21.3.2",
     "flake8",
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index b3a93212f11f..933a6692339c 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1961,7 +1961,7 @@ async def on_make_leave_request(
         return event
 
     async def on_send_leave_request(self, origin: str, pdu: EventBase) -> None:
-        """ We have received a leave event for a room. Fully process it."""
+        """We have received a leave event for a room. Fully process it."""
         event = pdu
 
         logger.debug(
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index 3c43f3258627..fda8da21b79c 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -454,7 +454,7 @@ class attribute containing a pre-compiled regular expression. The automatic
     """
 
     def register(self, http_server):
-        """ Register this servlet with the given HTTP server. """
+        """Register this servlet with the given HTTP server."""
         patterns = getattr(self, "PATTERNS", None)
         if patterns:
             for method in ("GET", "PUT", "POST", "DELETE"):
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index 7ced4c543c26..2ad7a200bb6a 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -571,7 +571,7 @@ async def _process_position(
     def on_REMOTE_SERVER_UP(
         self, conn: IReplicationConnection, cmd: RemoteServerUpCommand
     ):
-        """"Called when get a new REMOTE_SERVER_UP command."""
+        """Called when get a new REMOTE_SERVER_UP command."""
         self._replication_data_handler.on_remote_server_up(cmd.data)
 
         self._notifier.notify_remote_server_up(cmd.data)
diff --git a/synapse/types.py b/synapse/types.py
index e52cd7ffd4b9..0bdf32659c54 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -284,14 +284,14 @@ class RoomAlias(DomainSpecificString):
 
 @attr.s(slots=True, frozen=True, repr=False)
 class RoomID(DomainSpecificString):
-    """Structure representing a room id. """
+    """Structure representing a room id."""
 
     SIGIL = "!"
 
 
 @attr.s(slots=True, frozen=True, repr=False)
 class EventID(DomainSpecificString):
-    """Structure representing an event id. """
+    """Structure representing an event id."""
 
     SIGIL = "$"
 
diff --git a/tests/handlers/test_appservice.py b/tests/handlers/test_appservice.py
index 5d6cc2885f53..024c5e963cd2 100644
--- a/tests/handlers/test_appservice.py
+++ b/tests/handlers/test_appservice.py
@@ -26,7 +26,7 @@
 
 
 class AppServiceHandlerTestCase(unittest.TestCase):
-    """ Tests the ApplicationServicesHandler. """
+    """Tests the ApplicationServicesHandler."""
 
     def setUp(self):
         self.mock_store = Mock()
diff --git a/tests/handlers/test_directory.py b/tests/handlers/test_directory.py
index 1908d3c2c6fb..7a8041ab4437 100644
--- a/tests/handlers/test_directory.py
+++ b/tests/handlers/test_directory.py
@@ -27,7 +27,7 @@
 
 
 class DirectoryTestCase(unittest.HomeserverTestCase):
-    """ Tests the directory service. """
+    """Tests the directory service."""
 
     def make_homeserver(self, reactor, clock):
         self.mock_federation = Mock()
diff --git a/tests/handlers/test_profile.py b/tests/handlers/test_profile.py
index 5330a9b34e22..cdb41101b3c4 100644
--- a/tests/handlers/test_profile.py
+++ b/tests/handlers/test_profile.py
@@ -23,7 +23,7 @@
 
 
 class ProfileTestCase(unittest.HomeserverTestCase):
-    """ Tests profile management. """
+    """Tests profile management."""
 
     def make_homeserver(self, reactor, clock):
         self.mock_federation = Mock()
diff --git a/tests/handlers/test_register.py b/tests/handlers/test_register.py
index bd4319052338..c51763f41a3a 100644
--- a/tests/handlers/test_register.py
+++ b/tests/handlers/test_register.py
@@ -28,7 +28,7 @@
 
 
 class RegistrationTestCase(unittest.HomeserverTestCase):
-    """ Tests the RegistrationHandler. """
+    """Tests the RegistrationHandler."""
 
     def make_homeserver(self, reactor, clock):
         hs_config = self.default_config()
diff --git a/tests/handlers/test_sync.py b/tests/handlers/test_sync.py
index c8b43305f433..84f05f6c584c 100644
--- a/tests/handlers/test_sync.py
+++ b/tests/handlers/test_sync.py
@@ -22,7 +22,7 @@
 
 
 class SyncTestCase(tests.unittest.HomeserverTestCase):
-    """ Tests Sync Handler. """
+    """Tests Sync Handler."""
 
     def prepare(self, reactor, clock, hs):
         self.hs = hs
diff --git a/tests/rest/client/v1/test_events.py b/tests/rest/client/v1/test_events.py
index 852bda408c7f..2789d5154660 100644
--- a/tests/rest/client/v1/test_events.py
+++ b/tests/rest/client/v1/test_events.py
@@ -23,7 +23,7 @@
 
 
 class EventStreamPermissionsTestCase(unittest.HomeserverTestCase):
-    """ Tests event streaming (GET /events). """
+    """Tests event streaming (GET /events)."""
 
     servlets = [
         events.register_servlets,
diff --git a/tests/rest/client/v1/test_presence.py b/tests/rest/client/v1/test_presence.py
index 409f3949dc09..597e4c67de4f 100644
--- a/tests/rest/client/v1/test_presence.py
+++ b/tests/rest/client/v1/test_presence.py
@@ -24,7 +24,7 @@
 
 
 class PresenceTestCase(unittest.HomeserverTestCase):
-    """ Tests presence REST API. """
+    """Tests presence REST API."""
 
     user_id = "@sid:red"
 
diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py
index 5b1096d09112..e94566ffd70b 100644
--- a/tests/rest/client/v1/test_rooms.py
+++ b/tests/rest/client/v1/test_rooms.py
@@ -64,7 +64,7 @@ async def _insert_client_ip(*args, **kwargs):
 
 
 class RoomPermissionsTestCase(RoomBase):
-    """ Tests room permissions. """
+    """Tests room permissions."""
 
     user_id = "@sid1:red"
     rmcreator_id = "@notme:red"
@@ -377,7 +377,7 @@ def test_leave_permissions(self):
 
 
 class RoomsMemberListTestCase(RoomBase):
-    """ Tests /rooms/$room_id/members/list REST events."""
+    """Tests /rooms/$room_id/members/list REST events."""
 
     user_id = "@sid1:red"
 
@@ -416,7 +416,7 @@ def test_get_member_list_mixed_memberships(self):
 
 
 class RoomsCreateTestCase(RoomBase):
-    """ Tests /rooms and /rooms/$room_id REST events. """
+    """Tests /rooms and /rooms/$room_id REST events."""
 
     user_id = "@sid1:red"
 
@@ -502,7 +502,7 @@ def test_post_room_invitees_ratelimit(self):
 
 
 class RoomTopicTestCase(RoomBase):
-    """ Tests /rooms/$room_id/topic REST events. """
+    """Tests /rooms/$room_id/topic REST events."""
 
     user_id = "@sid1:red"
 
@@ -566,7 +566,7 @@ def test_rooms_topic_with_extra_keys(self):
 
 
 class RoomMemberStateTestCase(RoomBase):
-    """ Tests /rooms/$room_id/members/$user_id/state REST events. """
+    """Tests /rooms/$room_id/members/$user_id/state REST events."""
 
     user_id = "@sid1:red"
 
@@ -790,7 +790,7 @@ def test_autojoin_rooms(self):
 
 
 class RoomMessagesTestCase(RoomBase):
-    """ Tests /rooms/$room_id/messages/$user_id/$msg_id REST events. """
+    """Tests /rooms/$room_id/messages/$user_id/$msg_id REST events."""
 
     user_id = "@sid1:red"
 
@@ -838,7 +838,7 @@ def test_rooms_messages_sent(self):
 
 
 class RoomInitialSyncTestCase(RoomBase):
-    """ Tests /rooms/$room_id/initialSync. """
+    """Tests /rooms/$room_id/initialSync."""
 
     user_id = "@sid1:red"
 
@@ -879,7 +879,7 @@ def test_initial_sync(self):
 
 
 class RoomMessageListTestCase(RoomBase):
-    """ Tests /rooms/$room_id/messages REST events. """
+    """Tests /rooms/$room_id/messages REST events."""
 
     user_id = "@sid1:red"
 
diff --git a/tests/rest/client/v1/test_typing.py b/tests/rest/client/v1/test_typing.py
index 0aad48a162b4..44e22ca999cf 100644
--- a/tests/rest/client/v1/test_typing.py
+++ b/tests/rest/client/v1/test_typing.py
@@ -26,7 +26,7 @@
 
 
 class RoomTypingTestCase(unittest.HomeserverTestCase):
-    """ Tests /rooms/$room_id/typing/$user_id REST API. """
+    """Tests /rooms/$room_id/typing/$user_id REST API."""
 
     user_id = "@sid:red"
 
diff --git a/tests/storage/test_base.py b/tests/storage/test_base.py
index 3b45a7efd899..ddad44bd6cbb 100644
--- a/tests/storage/test_base.py
+++ b/tests/storage/test_base.py
@@ -27,7 +27,7 @@
 
 
 class SQLBaseStoreTestCase(unittest.TestCase):
-    """ Test the "simple" SQL generating methods in SQLBaseStore. """
+    """Test the "simple" SQL generating methods in SQLBaseStore."""
 
     def setUp(self):
         self.db_pool = Mock(spec=["runInteraction"])