diff --git a/m20/Dockerfile b/m20/Dockerfile
index 791053e..7ebdefc 100644
--- a/m20/Dockerfile
+++ b/m20/Dockerfile
@@ -1,7 +1,7 @@
-FROM alpine:latest
+FROM alpine:3.21
 
 RUN apk add --no-cache make gcc-arm-none-eabi newlib-arm-none-eabi
 
 WORKDIR /opt/m20
 
-CMD set -e && make clean && make
\ No newline at end of file
+CMD set -e && make clean && make