diff --git a/tests/requirements-py3.txt b/tests/requirements-py3.txt
index 00c56084d..b51177abb 100644
--- a/tests/requirements-py3.txt
+++ b/tests/requirements-py3.txt
@@ -1,8 +1,9 @@
 # Tests requirements
 attrs
 dataclasses; python_version == '3.6'
-mitmproxy; python_version >= '3.6'
-mitmproxy<4.0.0; python_version < '3.6'
+mitmproxy; python_version >= '3.7'
+mitmproxy >= 4, < 5; python_version >= '3.6' and python_version < '3.7'
+mitmproxy < 4; python_version < '3.6'
 # https://github.com/pytest-dev/pytest-twisted/issues/93
 pytest != 5.4, != 5.4.1
 pytest-azurepipelines
diff --git a/tox.ini b/tox.ini
index 11882c03f..4f5531aea 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,7 @@ deps =
     -rtests/requirements-py3.txt
     # Extras
     boto3>=1.13.0
-    botocore>=1.3.23
+    botocore>=1.4.87
     Pillow>=3.4.2
 passenv =
     S3_TEST_FILE_URI
@@ -76,7 +76,7 @@ deps =
     zope.interface==4.1.3
     -rtests/requirements-py3.txt
     # Extras
-    botocore==1.3.23
+    botocore==1.4.87
     google-cloud-storage==1.29.0
     Pillow==3.4.2