diff --git a/requirements.txt b/requirements.txt
index 84c8d38..156f1b6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,8 +1,9 @@
 # Version numbers of python modules in this file is mostly used by Travis CI,
 # iRedMail installs the binary packages from yum/apt/ports tree offerred by
 # Linux/BSD vendors directly, not from https://pypi.org/.
-requests==2.22.0
+MySQL-python==1.2.5; python_version < '3.0'
+mysql-connector-python==8.0.17; python_version >= '3.0'
+psycopg2==2.8.3
 python-ldap==3.2.0
-MySQL-python==1.2.5
+requests==2.22.0
 web.py==0.40.dev1
-psycopg2==2.8.3