diff --git a/runtime.txt b/runtime.txt
index 4b38fc9ad7899f5e9f5158299ba079d03fe90231..fdf79660d96060801ad21194c13c45befda30ab0 100644
--- a/runtime.txt
+++ b/runtime.txt
@@ -1 +1 @@
-python-2.7.13
+python-2.7.12