diff --git a/Dockerfile b/Dockerfile
index f1019de..760278a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,8 @@
-FROM alpine:3.15
+FROM alpine:3.21
+
 RUN \
-  apk -U upgrade && apk add mosquitto mosquitto-clients openssl && \
+  apk -U upgrade && \
+  apk add mosquitto mosquitto-clients openssl && \
   echo "log_dest stdout" >/etc/mosquitto/mosquitto.conf && \
   echo "listener 1883" >>/etc/mosquitto/mosquitto.conf && \
   echo "allow_anonymous true" >>/etc/mosquitto/mosquitto.conf