diff --git a/README.md b/README.md
index e463ac5ee..8fc7c993a 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Contains:
 
 ### Python version
 
-At the moment we run Python 3.6 in production. You will run into problems if you try to use Python 3.5 or older, or Python 3.7 or newer.
+We run python 3.9 both locally and in production.
 
 ### AWS credentials
 
diff --git a/runtime.txt b/runtime.txt
index 62ce9c02a..305091cae 100644
--- a/runtime.txt
+++ b/runtime.txt
@@ -1 +1 @@
-python-3.6.x
+python-3.9.x