diff --git a/telethon/client/telegrambaseclient.py b/telethon/client/telegrambaseclient.py
index d4e353e4..4fae4cb8 100644
--- a/telethon/client/telegrambaseclient.py
+++ b/telethon/client/telegrambaseclient.py
@@ -398,11 +398,6 @@ class TelegramBaseClient(abc.ABC):
 
         self._authorized = None  # None = unknown, False = no, True = yes
 
-        # Update state (for catching up after a disconnection)
-        # TODO Get state from channels too
-        self._state_cache = StateCache(
-            self.session.get_update_state(0), self._log)
-
         # Some further state for subclasses
         self._event_builders = []
 
diff --git a/telethon/sessions/abstract.py b/telethon/sessions/abstract.py
index 8c0a717e..11cc63a1 100644
--- a/telethon/sessions/abstract.py
+++ b/telethon/sessions/abstract.py
@@ -98,7 +98,7 @@ class Session(ABC):
         raise NotImplementedError
 
     @abstractmethod
-    async def get_update_states(self):
+    def get_update_states(self):
         """
         Returns an iterable over all known pairs of ``(entity ID, update state)``.
         """
diff --git a/telethon/sessions/memory.py b/telethon/sessions/memory.py
index 27d7907b..721b6d9a 100644
--- a/telethon/sessions/memory.py
+++ b/telethon/sessions/memory.py
@@ -77,7 +77,7 @@ class MemorySession(Session):
     def set_update_state(self, entity_id, state):
         self._update_states[entity_id] = state
 
-    async def get_update_states(self):
+    def get_update_states(self):
         return self._update_states.items()
 
     def close(self):
diff --git a/telethon/sessions/sqlite.py b/telethon/sessions/sqlite.py
index 6c9d042e..77105f64 100644
--- a/telethon/sessions/sqlite.py
+++ b/telethon/sessions/sqlite.py
@@ -215,7 +215,7 @@ class SQLiteSession(MemorySession):
                       entity_id, state.pts, state.qts,
                       state.date.timestamp(), state.seq)
 
-    async def get_update_states(self):
+    def get_update_states(self):
         c = self._cursor()
         try:
             rows = c.execute('select id, pts, qts, date, seq from update_state').fetchall()
@@ -332,7 +332,7 @@ class SQLiteSession(MemorySession):
         return self._execute(
             'select id, hash from entities where name = ?', name)
 
-    async def get_entity_rows_by_id(self, id, exact=True):
+    def get_entity_rows_by_id(self, id, exact=True):
         if exact:
             return self._execute(
                 'select id, hash from entities where id = ?', id)
diff --git a/telethon/sessions/string.py b/telethon/sessions/string.py
index 25646aa9..fb971d82 100644
--- a/telethon/sessions/string.py
+++ b/telethon/sessions/string.py
@@ -11,15 +11,6 @@ _STRUCT_PREFORMAT = '>B{}sH256s'
 CURRENT_VERSION = '1'
 
 
-class _AsyncString(str):
-    """
-    Ugly hack to enable awaiting strings.
-    """
-    def __await__(self):
-        yield
-        return self
-
-
 class StringSession(MemorySession):
     """
     This session file can be easily saved and loaded as a string. According
@@ -59,17 +50,14 @@ class StringSession(MemorySession):
         return base64.urlsafe_b64decode(x)
 
     def save(self: Session):
-        # save should be async but that would break code which relies on sync StringSession.
-        # Return a type which behaves like a string for all intents and purposes, but can be awaited.
-        # The await is necessary for the library to save all sessions in the same way.
         if not self.auth_key:
-            return _AsyncString('')
+            return ''
 
         ip = ipaddress.ip_address(self.server_address).packed
-        return _AsyncString(CURRENT_VERSION + StringSession.encode(struct.pack(
+        return CURRENT_VERSION + StringSession.encode(struct.pack(
             _STRUCT_PREFORMAT.format(len(ip)),
             self.dc_id,
             ip,
             self.port,
             self.auth_key.key
-        )))
+        ))