diff --git a/ecs/Dockerfile b/ecs/Dockerfile
index 549516f..32e06f3 100644
--- a/ecs/Dockerfile
+++ b/ecs/Dockerfile
@@ -27,7 +27,7 @@ RUN mkdir runtime \
  && rm bin/ejabberd bin/ejabberd.bat
 
 # Runtime container
-FROM alpine:edge
+FROM alpine:3.9
 ARG VERSION
 ENV TERM=xterm \
     LC_ALL=C.UTF-8 \
diff --git a/mix/Dockerfile b/mix/Dockerfile
index 1ae6f8e..716aff6 100644
--- a/mix/Dockerfile
+++ b/mix/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:edge
+FROM alpine:3.9
 LABEL maintainer="ProcessOne <contact@process-one.net>" \
       product="Ejabberd mix development environment"