diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 41ed8cc9f..dc3fe054e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -6,6 +6,16 @@ Before we can merge your Pull-Request here are some guidelines that you need to
 These guidelines exist not to annoy you, but to keep the code base clean,
 unified and future proof.
 
+## We only accept PRs  to "master"
+
+Our branching strategy is summed up with "everything to master first", even
+bugfixes and we then merge them into the stable branches. You should only 
+open pull requests against the master branch. Otherwise we cannot accept the PR.
+
+There is one exception to the rule, when we merged a bug into some stable branches
+we do occasionally accept pull requests that merge the same bug fix into earlier
+branches.
+
 ## Coding Standard
 
 We use PSR-1 and PSR-2: