diff --git a/app.yaml b/app.yaml
index 29b1c0d9f55c375902cfb9acef1545d2dd950ccf..0b4e957ae267e4734d382bc034418ec4d0ac42ca 100644
--- a/app.yaml
+++ b/app.yaml
@@ -1,5 +1,5 @@
 ---
-runtime: go112
+runtime: go113
 
 main: ./cmd/go_httpbin