diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e24e1c..8ededce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,18 @@ All user visible changes to this project will be documented in this file. This p
 
 
 
+## [alpine3.21-r0] · 2024-12-06
+[alpine3.21-r0]: /../../tree/alpine3.21-r0
+
+[Diff](/../../compare/alpine3.20-r3...alpine3.21-r0)
+
+### Upgraded
+
+- [Alpine Linux] 3.21: <https://www.alpinelinux.org/posts/Alpine-3.21.0-released.html>
+
+
+
+
 ## [alpine3.20-r3] · 2024-09-09
 [alpine3.20-r3]: /../../tree/alpine3.20-r3
 
diff --git a/Dockerfile b/Dockerfile
index e58b4bc..6063c65 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,8 +1,8 @@
 # https://hub.docker.com/_/alpine
-ARG alpine_ver=3.20
+ARG alpine_ver=3.21
 FROM alpine:${alpine_ver}
 
-ARG build_rev=3
+ARG build_rev=0
 
 
 # Install Rsync and SSH.
diff --git a/README.md b/README.md
index adae00c..c925bf9 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Rsync + SSH Docker image
 
 ## Supported tags and respective `Dockerfile` links
 
-- [`alpine3.20-r3`, `alpine3.20`, `alpine`, `latest`][d1]
+- [`alpine3.21-r0`, `alpine3.21`, `alpine`, `latest`][d1]