diff --git a/setup.py b/setup.py
index abecea8..3ca9484 100644
--- a/setup.py
+++ b/setup.py
@@ -26,7 +26,7 @@
     url="https://github.com/platformsh/colander-tools",
     packages=find_packages(),
     install_requires=[
-        "colander",
+        "colander < 2",
         "pytz",
         "netaddr",
         "six",