diff --git a/{{cookiecutter.project_slug}}/runtime.txt b/{{cookiecutter.project_slug}}/runtime.txt
index 94159178..e16ddff2 100644
--- a/{{cookiecutter.project_slug}}/runtime.txt
+++ b/{{cookiecutter.project_slug}}/runtime.txt
@@ -1 +1 @@
-{% if cookiecutter.use_python3 == 'y' -%}python-3.5.1{% else %}python-2.7.10{%- endif %}
+{% if cookiecutter.use_python3 == 'y' -%}python-3.5.3{% else %}python-2.7.10{%- endif %}