diff --git a/README.rst b/README.rst
index bad1d9c..f77c72e 100644
--- a/README.rst
+++ b/README.rst
@@ -121,7 +121,7 @@ Supported commands:
    errors during every synchronization run :-)."
    "``-c``, ``--color=CHOICE,`` ``--colour=CHOICE``","Specify whether ANSI escape sequences for text and background colors and
    text styles are to be used or not, depending on the value of ``CHOICE``:
-   
+
    - The values 'always', 'true', 'yes' and '1' enable colors.
    - The values 'never', 'false', 'no' and '0' disable colors.
    - When the value is 'auto' (this is the default) then colors will
@@ -405,6 +405,47 @@ In the future more backends may be added:
   generated ten years ago (circa 2008) because I have megabytes of such chat
   logs stored in backups 🙂.
 
+
+Google Hangouts Notes
+---------------------
+Google Hangouts has recently changed their authorization flow and it cannot easily be automated. Here are the steps to manually authorize Google Hangouts:
+
+----
+
+1) Install hangups (https://github.com/tdryer/hangups). I recommend using the latest git version due to the fragile nature of its reverse engineered protocol:
+
+.. code-block:: bash
+
+  pip install 'git+https://github.com/tdryer/hangups'
+
+----
+
+2) To authorize hangups, you must include an oauth cookie. Run the following python script, open the link in a browser, log in to Google, open the Developer Tools (Ctrl+Shift+i in Firefox), go to the "Storage" tab, and copy the cookie labeled "oauth token". Paste this token string into the terminal prompt. Now hangups will be authorized with a token in `$HOME/.cache/hangups/refresh_token.txt`, and chat_archive will read the token from there.
+
+.. code-block:: python
+
+  #!/usr/bin/env python3
+
+  import os, hangups, requests, appdirs
+
+  print('Open this URL:')
+  print(hangups.auth.OAUTH2_LOGIN_URL)
+
+  authorization_code = input('Enter oauth_code cookie value: ')
+
+  with requests.Session() as session:
+      session.headers = {'user-agent': hangups.auth.USER_AGENT}
+      access_token, refresh_token = hangups.auth._auth_with_code(
+          session, authorization_code
+      )
+
+  dirs = appdirs.AppDirs('hangups', 'hangups')
+  token_path = os.path.join(dirs.user_cache_dir, 'refresh_token.txt')
+  hangups.auth.RefreshTokenCache(token_path).set(refresh_token)
+
+----
+
+
 History
 -------
 
diff --git a/chat_archive/backends/hangouts.py b/chat_archive/backends/hangouts.py
index ab8b591..d4bc7f4 100644
--- a/chat_archive/backends/hangouts.py
+++ b/chat_archive/backends/hangouts.py
@@ -12,6 +12,7 @@
 import html
 import os
 import time
+import appdirs
 
 # External dependencies.
 import hangups
@@ -70,6 +71,10 @@ def client(self):
         """The hangups client object."""
         # Make sure the directory with cached credentials exists.
         ensure_directory_exists(os.path.dirname(self.cookie_file))
+
+        dirs = appdirs.AppDirs('hangups', 'hangups')
+        token_path = os.path.join(dirs.user_cache_dir, 'refresh_token.txt')
+
         return Client(
             get_auth(
                 GoogleAccountCredentials(
@@ -81,7 +86,7 @@ def client(self):
                         description="Google account password",
                     ),
                 ),
-                RefreshTokenCache(self.cookie_file),
+                RefreshTokenCache(token_path)
             )
         )
 
diff --git a/chat_archive/backends/slack.py b/chat_archive/backends/slack.py
index c322e4d..f946c23 100644
--- a/chat_archive/backends/slack.py
+++ b/chat_archive/backends/slack.py
@@ -10,6 +10,7 @@
 import datetime
 import decimal
 import html
+import time
 
 # External dependencies.
 from humanfriendly import Spinner
@@ -135,10 +136,12 @@ def import_messages(self, source, conversation_in_db):
                     external_id=message["ts"],
                     html=html,
                     raw=message["text"],
-                    sender=self.get_or_create_contact(external_id=message["user"]),
+                    sender=self.get_or_create_contact(external_id=message.get("user")),
                     text=html_to_text(html),
                     timestamp=datetime.datetime.utcfromtimestamp(float(message["ts"])),
                 )
+
+            time.sleep(0.01)
         if not conversation_in_db.import_complete:
             conversation_in_db.import_complete = True
 
diff --git a/chat_archive/backends/telegram.py b/chat_archive/backends/telegram.py
index 91c48cc..248b0ac 100644
--- a/chat_archive/backends/telegram.py
+++ b/chat_archive/backends/telegram.py
@@ -15,6 +15,7 @@
 # Standard library modules.
 import asyncio
 import os
+import pytz
 
 # External dependencies.
 from property_manager import lazy_property, mutable_property, required_property
@@ -121,7 +122,8 @@ async def connect_then_sync(self):
                 )
                 if not conversation_in_db.import_complete:
                     await self.perform_initial_sync(dialog, conversation_in_db)
-                elif dialog.date > conversation_in_db.last_modified:
+
+                elif dialog.date > conversation_in_db.last_modified.replace(tzinfo=pytz.utc):
                     logger.info("Conversation was updated (%s) ..", dialog.id)
                     await self.update_conversation(dialog, conversation_in_db)
                     conversation_in_db.last_modified = dialog.date