diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3c90df0..d2165db 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,6 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version:
-        - '3.0'
         - '3.1'
         - '3.2'
         - '3.3'
diff --git a/docker/Dockerfile b/docker/Dockerfile
index bc2033a..4441df7 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,11 +1,11 @@
-FROM alpine:3.21.3
+FROM alpine:3.22.0
 
 EXPOSE 5353 8080
 
 ARG DYNDNSD_VERSION
 
 RUN apk --no-cache add openssl ca-certificates && \
-    apk --no-cache add ruby ruby-etc ruby-io-console ruby-json ruby-webrick && \
+    apk --no-cache add ruby ruby-webrick && \
     apk --no-cache add --virtual .build-deps linux-headers ruby-dev build-base tzdata && \
     gem install --no-document dyndnsd -v ${DYNDNSD_VERSION} && \
     rm -rf /usr/lib/ruby/gems/*/cache/ && \
diff --git a/docker/ci/Dockerfile b/docker/ci/Dockerfile
index e4fbc9d..7b0bfab 100644
--- a/docker/ci/Dockerfile
+++ b/docker/ci/Dockerfile
@@ -1,11 +1,11 @@
-FROM alpine:3.21.3
+FROM alpine:3.22.0
 
 EXPOSE 5353 8080
 
 COPY pkg/dyndnsd-*.gem /tmp/dyndnsd.gem
 
 RUN apk --no-cache add openssl ca-certificates && \
-    apk --no-cache add ruby ruby-etc ruby-io-console ruby-json ruby-webrick && \
+    apk --no-cache add ruby ruby-webrick && \
     apk --no-cache add --virtual .build-deps linux-headers ruby-dev build-base tzdata && \
     gem install --no-document /tmp/dyndnsd.gem && \
     rm -rf /usr/lib/ruby/gems/*/cache/ && \