diff --git a/fixed-requirements.txt b/fixed-requirements.txt
index d8e3f1ffd2..ea66e50b9e 100644
--- a/fixed-requirements.txt
+++ b/fixed-requirements.txt
@@ -12,11 +12,13 @@ oslo.config>=1.12.1,<1.13
 oslo.utils<3.1.0
 six==1.10.0
 pyyaml>=3.12,<4.0
-requests[security]>=2.18.1,<2.19
+requests[security]==2.18.1
 apscheduler==3.3.1
 gitpython==2.1.5
 jsonschema==2.6.0
-mongoengine==0.13.0
+# Note: mongoengine v0.13.0 introduces memory usage regression so we can't
+# upgrade - https://github.com/StackStorm/st2/pull/3597
+mongoengine==0.12.0
 pymongo==3.4.0
 passlib==1.7.1
 lockfile==0.12.2
@@ -40,3 +42,4 @@ routes==2.4.1
 flex==6.10.0
 webob==1.7.3
 prance==0.6.1
+certifi==2017.4.17
diff --git a/requirements.txt b/requirements.txt
index 50bfd81ae4..d70b5c6432 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,7 @@
 apscheduler==3.3.1
 argcomplete
 bcrypt
+certifi==2017.4.17
 eventlet==0.19.0
 flex==6.10.0
 git+https://github.com/Kami/entrypoints.git@dont_use_backports#egg=entrypoints
@@ -17,7 +18,7 @@ jsonschema==2.6.0
 kombu==4.0.2
 lockfile==0.12.2
 mock
-mongoengine==0.13.0
+mongoengine==0.12.0
 networkx==1.11
 nose
 oslo.config<1.13,>=1.12.1
@@ -38,7 +39,7 @@ python-keyczar==0.716
 pytz
 pyyaml<4.0,>=3.12
 rednose
-requests[security]<2.19,>=2.18.1
+requests[security]==2.18.1
 retrying==1.3.3
 routes==2.4.1
 semver==2.7.7
diff --git a/st2client/requirements.txt b/st2client/requirements.txt
index 8ee9aa5469..b9ac2c5156 100644
--- a/st2client/requirements.txt
+++ b/st2client/requirements.txt
@@ -7,6 +7,7 @@ python-dateutil
 python-editor==1.0.1
 pytz
 pyyaml<4.0,>=3.11
-requests[security]<2.12,>=2.11.1
+requests[security]==2.18.1
+certifi==2017.4.17
 six==1.10.0
 sseclient==0.0.12
diff --git a/st2client/setup.py b/st2client/setup.py
index 7cb1916f19..2f2db7a5bb 100644
--- a/st2client/setup.py
+++ b/st2client/setup.py
@@ -56,7 +56,8 @@
         'prettytable',
         'python-dateutil',
         'pyyaml<4.0,>=3.11',
-        'requests<3.0,>=2.7.0',
+        'requests[security]==2.18.1',
+        'certifi',
         'six==1.10.0'
     ],
     dependency_links=[],
diff --git a/st2client/st2client/base.py b/st2client/st2client/base.py
index 7ffeed2e12..f241f67bf3 100644
--- a/st2client/st2client/base.py
+++ b/st2client/st2client/base.py
@@ -23,9 +23,9 @@
 
 import six
 import requests
-import urllib3
 
-from urllib3.exceptions import InsecureRequestWarning
+# pylint: disable=import-error
+from requests.packages.urllib3.exceptions import InsecureRequestWarning
 
 from st2client import models
 from st2client.config_parser import CLIConfigParser
@@ -107,7 +107,6 @@ def get_client(self, args, debug=False):
         silence_ssl_warnings = rc_config.get('general', {}).get('silence_ssl_warnings', False)
         if silence_ssl_warnings:
             # pylint: disable=no-member
-            urllib3.disable_warnings(InsecureRequestWarning)
             requests.packages.urllib3.disable_warnings(InsecureRequestWarning)
 
         # We skip automatic authentication for some commands such as auth
diff --git a/st2common/in-requirements.txt b/st2common/in-requirements.txt
index 149062478a..f1490bf944 100644
--- a/st2common/in-requirements.txt
+++ b/st2common/in-requirements.txt
@@ -27,3 +27,4 @@ routes
 flex
 webob
 prance
+certifi
diff --git a/test-requirements.txt b/test-requirements.txt
index b9b2a038e1..31eb8e24da 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -20,7 +20,7 @@ nose-parallel
 # Required by st2client tests
 pyyaml<4.0,>=3.12
 RandomWords
-gunicorn==19.6.0
+gunicorn==19.7.1
 psutil
 webtest==2.0.25
 rstcheck>=3.1.0,<3.2