diff --git a/client/Dockerfile b/client/Dockerfile
index e7bc52a..c261962 100644
--- a/client/Dockerfile
+++ b/client/Dockerfile
@@ -11,7 +11,7 @@ ARG SITE_URL=http://localhost:3100
 RUN SITE_URL=${SITE_URL} npm run build
 
 # ---- runtime: unprivileged nginx (runs as uid 101, listens on 8080) ----
-FROM nginxinc/nginx-unprivileged:1.29-alpine AS runtime
+FROM nginxinc/nginx-unprivileged:1.31-alpine AS runtime
 ARG APP_VERSION=dev
 LABEL org.opencontainers.image.title="cstimer-web" \
       org.opencontainers.image.version="${APP_VERSION}"