diff --git a/Dockerfile b/Dockerfile
index f9bc6eb..7ada35f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM openresty/openresty:alpine-fat
+FROM openresty/openresty:1.19.9.1-7-alpine-fat
 
 # allowed domains should be lua match pattern
 ENV DIFFIE_HELLMAN='' \