diff --git a/dev_requirements.txt b/dev_requirements.txt
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -1,8 +1,8 @@
-pytest >= 3.3.0, < 3.8
-pytest-runner < 4.3
-pytest-sugar >= 0.7.0, < 0.10
-pytest-benchmark < 3.2
-pytest-localserver < 0.5
-mock < 2.1
-Sphinx < 1.8
-WebTest < 2.1
+pytest >= 4.6.6, < 4.7
+pytest-sugar >= 0.9.2, < 0.10
+pytest-benchmark >= 3.2.2, < 3.3
+pytest-localserver >= 0.5.0, < 0.6
+mock >= 3.0.0, < 3.1
+Sphinx >= 1.8.0, < 1.9
+WebTest >= 2.0.3, < 2.1
+isort == 4.3.21