diff --git a/Dockerfile b/Dockerfile
index 3f3b0aa..607024f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.15 as builder
+FROM docker.io/alpine:3.16 as builder
 
 RUN apk --no-cache add \
     rpcgen \
@@ -56,7 +56,7 @@ RUN cd /tmp/pigeonhole && \
     --disable-static && \
     make && make install
 
-FROM thallian/confd-env:latest
+FROM docker.io/thallian/confd-env:3.16
 
 COPY --from=builder /lib/dovecot/ /lib/dovecot/
 COPY --from=builder /libexec/dovecot/ /libexec/dovecot/