diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index cb098be76f..b19f80d3f3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -14,6 +14,8 @@
 Thanks for taking the time to contribute!
 This document summarizes the deployment principles which govern our project.
 
+:exclamation: All pull requests are required to be submitted against `experimental` branch.
+
 ## Building 'in the open'
 
 - Our users appreciate the transparency of our project; in this context, building "in the open" means that anyone can: