diff --git a/pyrogram/__init__.py b/pyrogram/__init__.py
index a290ca0f..78942791 100644
--- a/pyrogram/__init__.py
+++ b/pyrogram/__init__.py
@@ -16,7 +16,12 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with Pyrogram.  If not, see <http://www.gnu.org/licenses/>.
 
-__copyright__ = "Copyright (C) 2017-2018 Dan Tès <https://github.com/delivrance>".encode(errors="replace").decode()
+import sys
+
+__copyright__ = "Copyright (C) 2017-2018 Dan Tès <https://github.com/delivrance>".replace(
+    "\xe8",
+    "e" if sys.getfilesystemencoding() == "ascii" else "\xe8"
+)
 __license__ = "GNU Lesser General Public License v3 or later (LGPLv3+)"
 __version__ = "0.4.2"
 
diff --git a/pyrogram/client/client.py b/pyrogram/client/client.py
index a0b4586a..9c838e0d 100644
--- a/pyrogram/client/client.py
+++ b/pyrogram/client/client.py
@@ -93,6 +93,9 @@ class Client:
         last_name (:obj:`str`, optional):
             Same purpose as *first_name*; pass a Last Name to avoid entering it manually. It can
             be an empty string: ""
+
+        workers (:obj:`int`, optional):
+            Thread pool size for handling incoming messages (updates). Defaults to 4.
     """
 
     INVITE_LINK_RE = re.compile(r"^(?:https?://)?t\.me/joinchat/(.+)$")
@@ -105,7 +108,8 @@ class Client:
                  phone_code: str or callable = None,
                  password: str = None,
                  first_name: str = None,
-                 last_name: str = None):
+                 last_name: str = None,
+                 workers: int = 4):
         self.session_name = session_name
         self.test_mode = test_mode
 
@@ -115,6 +119,8 @@ class Client:
         self.first_name = first_name
         self.last_name = last_name
 
+        self.workers = workers
+
         self.dc_id = None
         self.auth_key = None
         self.user_id = None
@@ -144,7 +150,14 @@ class Client:
         self.load_config()
         self.load_session(self.session_name)
 
-        self.session = Session(self.dc_id, self.test_mode, self.proxy, self.auth_key, self.config.api_id)
+        self.session = Session(
+            self.dc_id,
+            self.test_mode,
+            self.proxy,
+            self.auth_key,
+            self.config.api_id,
+            workers=self.workers
+        )
 
         terms = self.session.start()
 
@@ -243,7 +256,14 @@ class Client:
                 self.dc_id = e.x
                 self.auth_key = Auth(self.dc_id, self.test_mode, self.proxy).create()
 
-                self.session = Session(self.dc_id, self.test_mode, self.proxy, self.auth_key, self.config.api_id)
+                self.session = Session(
+                    self.dc_id,
+                    self.test_mode,
+                    self.proxy,
+                    self.auth_key,
+                    self.config.api_id,
+                    workers=self.workers
+                )
                 self.session.start()
 
                 r = self.send(
@@ -513,18 +533,51 @@ class Client:
                 peer_username = peer_username.lower()
                 self.peers_by_username[peer_username] = input_peer
 
+    def resolve_username(self, username: str):
+        username = username.lower().strip("@")
+
+        resolved_peer = self.send(
+            functions.contacts.ResolveUsername(
+                username=username
+            )
+        )  # type: types.contacts.ResolvedPeer
+
+        if type(resolved_peer.peer) is PeerUser:
+            input_peer = InputPeerUser(
+                user_id=resolved_peer.users[0].id,
+                access_hash=resolved_peer.users[0].access_hash
+            )
+            chat_id = input_peer.user_id
+        elif type(resolved_peer.peer) is PeerChannel:
+            input_peer = InputPeerChannel(
+                channel_id=resolved_peer.chats[0].id,
+                access_hash=resolved_peer.chats[0].access_hash
+            )
+            chat_id = input_peer.channel_id
+        else:
+            raise PeerIdInvalid
+
+        self.peers_by_username[username] = input_peer
+        self.peers_by_id[chat_id] = input_peer
+
+        return input_peer
+
     def resolve_peer(self, chat_id: int or str):
         if chat_id in ("self", "me"):
             return InputPeerSelf()
         else:
-            try:
-                return (
-                    self.peers_by_username[chat_id.lower().strip("@")]
-                    if isinstance(chat_id, str)
-                    else self.peers_by_id[chat_id]
-                )
-            except KeyError:
-                raise PeerIdInvalid
+            if type(chat_id) is str:
+                chat_id = chat_id.lower().strip("@")
+
+                try:
+                    return self.peers_by_username[chat_id]
+                except KeyError:
+                    return self.resolve_username(chat_id)
+            else:
+                try:
+                    return self.peers_by_id[chat_id]
+                except KeyError:
+                    raise PeerIdInvalid
 
     def get_me(self):
         """A simple method for testing the user authorization. Requires no parameters.
diff --git a/pyrogram/session/session.py b/pyrogram/session/session.py
index c399d9ec..23d686a4 100644
--- a/pyrogram/session/session.py
+++ b/pyrogram/session/session.py
@@ -60,7 +60,6 @@ class Session:
 
     INITIAL_SALT = 0x616e67656c696361
 
-    WORKERS = 4
     WAIT_TIMEOUT = 10
     MAX_RETRIES = 5
     ACKS_THRESHOLD = 8
@@ -68,13 +67,21 @@ class Session:
 
     notice_displayed = False
 
-    def __init__(self, dc_id: int, test_mode: bool, proxy: type, auth_key: bytes, api_id: str, is_cdn: bool = False):
+    def __init__(self,
+                 dc_id: int,
+                 test_mode: bool,
+                 proxy: type,
+                 auth_key: bytes,
+                 api_id: str,
+                 is_cdn: bool = False,
+                 workers: int = 2):
         if not Session.notice_displayed:
             print("Pyrogram v{}, {}".format(__version__, __copyright__))
             print("Licensed under the terms of the " + __license__, end="\n\n")
             Session.notice_displayed = True
 
         self.is_cdn = is_cdn
+        self.workers = workers
 
         self.connection = Connection(DataCenter(dc_id, test_mode), proxy)
 
@@ -115,7 +122,7 @@ class Session:
             try:
                 self.connection.connect()
 
-                for i in range(self.WORKERS):
+                for i in range(self.workers):
                     Thread(target=self.worker, name="Worker#{}".format(i + 1)).start()
 
                 Thread(target=self.recv, name="RecvThread").start()
@@ -175,7 +182,7 @@ class Session:
 
         self.connection.close()
 
-        for i in range(self.WORKERS):
+        for i in range(self.workers):
             self.recv_queue.put(None)
 
         log.debug("Session stopped")