diff --git a/requirements.txt b/requirements.txt
index a104833..952532a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,18 +1,18 @@
-atomicwrites==1.2.1
-attrs==18.2.0
-configparser==3.5.0
-coverage==4.5.2
-enum34==1.1.6
-flake8==3.6.0
-funcsigs==1.0.2
-mccabe==0.6.1
-more-itertools==4.3.0
-pathlib2==2.3.2
-pluggy==0.8.0
-py==1.7.0
-pycodestyle==2.4.0
-pyflakes==2.0.0
-pytest==4.0.1
-pytest-cov==2.6.0
-scandir==1.9.0
-six==1.11.0
+atomicwrites>=1.2.1
+attrs>=18.2.0
+configparser>=3.5.0
+coverage>=4.5.2
+enum34>=1.1.6
+flake8>=3.6.0
+funcsigs>=1.0.2
+mccabe>=0.6.1
+more-itertools>=4.3.0
+pathlib2>=2.3.2
+pluggy>=0.8.0
+py>=1.7.0
+pycodestyle>=2.4.0
+pyflakes>=2.0.0
+pytest>=4.0.1
+pytest-cov>=2.6.0
+scandir>=1.9.0
+six>=1.11.0