diff --git a/flatisfy/config.py b/flatisfy/config.py
index d879630..7f4bc28 100644
--- a/flatisfy/config.py
+++ b/flatisfy/config.py
@@ -126,7 +126,7 @@ def validate_config(config, check_with_data):
         assert config["backends"] is None or isinstance(config["backends"], list)  # noqa: E501
 
         assert isinstance(config["send_email"], bool)
-        assert config["smtp_server"] is None or isinstance(config["smtp_server"], (str, unicode))  # noqa: E501
+        assert config["smtp_server"] is None or isinstance(config["smtp_server"], str)  # noqa: E501
         assert config["smtp_port"] is None or isinstance(config["smtp_port"], int)  # noqa: E501
         assert config["smtp_to"] is None or isinstance(config["smtp_to"], list)
 
diff --git a/flatisfy/email.py b/flatisfy/email.py
index f33d79e..d35526e 100644
--- a/flatisfy/email.py
+++ b/flatisfy/email.py
@@ -4,6 +4,7 @@ Email notifications.
 """
 
 from __future__ import absolute_import, print_function, unicode_literals
+from builtins import str
 
 import logging
 import smtplib
@@ -72,11 +73,11 @@ def send_notification(config, flats):
     website_url = config["website_url"]
 
     for flat in flats:
-        title = unicode(flat.title)
-        flat_id = unicode(flat.id)
-        area = unicode(flat.area)
-        cost = unicode(flat.cost)
-        currency = unicode(flat.currency)
+        title = str(flat.title)
+        flat_id = str(flat.id)
+        area = str(flat.area)
+        cost = str(flat.cost)
+        currency = str(flat.currency)
 
         txt += (
             '- {}: {}#/flat/{} (area: {}, cost: {} {})\n'.format(