diff --git a/modules/doc/install.rst b/modules/doc/install.rst
index bf0038767689cd2a15be79e3c7cf472d55fcd0dd..4d8d306a4cac6bb8bf339070af0d27b752dbbc3b 100644
--- a/modules/doc/install.rst
+++ b/modules/doc/install.rst
@@ -57,6 +57,9 @@ If you would like to use the :mod:`molecular mechanics <ost.mol.mm>` module:
 
 * `OpenMM <https://simtk.org/home/openmm>`_ (6.1)
 
+We do not provide backwards compatibility to Python 2.7. The last
+release supporting Python 2.7 is 1.11.0.
+
 
 Getting the Source Code
 --------------------------------------------------------------------------------