diff --git a/doc/source/installation.rst b/doc/source/installation.rst
index 9942594..8f7ae68 100644
--- a/doc/source/installation.rst
+++ b/doc/source/installation.rst
@@ -2,6 +2,8 @@
 Installation
 ============
 
+The client requires at least the version 4.0.9 of Almanach.
+
 At the command line::
 
     $ pip install python-almanachclient