diff --git a/requirements.txt b/requirements.txt
index c2be0a5..f6f0d3d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,8 @@
 pytz
-workalendar<8.0.0
+workalendar<8.0.0;python_version<="2.7.18"
+workalendar;python_version>"2.7.18"
 pandas>=0.23.4,<3.0.0
 requests
 six
 xlrd==1.2.0
-openpyxl
\ No newline at end of file
+openpyxl