diff --git a/requirements-dev.txt b/requirements-dev.txt
index 2cc3575..6fc9042 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,4 +1,4 @@
 chardet==3.0.4
-Cython==0.27.3
+Cython==0.28.5
 nose==1.3.7
-tox==2.9.1
\ No newline at end of file
+tox==3.4.0