diff --git a/.github/workflows/external_trigger.yml b/.github/workflows/external_trigger.yml
index d48dcfe..934f616 100644
--- a/.github/workflows/external_trigger.yml
+++ b/.github/workflows/external_trigger.yml
@@ -48,13 +48,30 @@ jobs:
             --header "Accept: application/vnd.oci.image.index.v1+json" \
             --header "Authorization: Bearer ${token}" \
             "https://ghcr.io/v2/${image}/manifests/${tag}")
-          multidigest=$(jq -r ".manifests[] | select(.platform.architecture == \"amd64\").digest?" <<< "${multidigest}")
-          digest=$(curl -s \
-            --header "Accept: application/vnd.docker.distribution.manifest.v2+json" \
-            --header "Accept: application/vnd.oci.image.manifest.v1+json" \
-            --header "Authorization: Bearer ${token}" \
-            "https://ghcr.io/v2/${image}/manifests/${multidigest}" \
-            | jq -r '.config.digest')
+          if jq -e '.layers // empty' <<< "${multidigest}" >/dev/null 2>&1; then
+            # If there's a layer element it's a single-arch manifest so just get that digest
+            digest=$(jq -r '.config.digest' <<< "${multidigest}")
+          else
+            # Otherwise it's multi-arch or has manifest annotations
+            if jq -e '.manifests[]?.annotations // empty' <<< "${multidigest}" >/dev/null 2>&1; then
+              # Check for manifest annotations and delete if found
+              multidigest=$(jq 'del(.manifests[] | select(.annotations))' <<< "${multidigest}")
+            fi
+            if [[ $(jq '.manifests | length' <<< "${multidigest}") -gt 1 ]]; then
+              # If there's still more than one digest, it's multi-arch
+              multidigest=$(jq -r ".manifests[] | select(.platform.architecture == \"amd64\").digest?" <<< "${multidigest}")
+            else
+              # Otherwise it's single arch
+              multidigest=$(jq -r ".manifests[].digest?" <<< "${multidigest}")
+            fi
+            if digest=$(curl -s \
+              --header "Accept: application/vnd.docker.distribution.manifest.v2+json" \
+              --header "Accept: application/vnd.oci.image.manifest.v1+json" \
+              --header "Authorization: Bearer ${token}" \
+              "https://ghcr.io/v2/${image}/manifests/${multidigest}"); then
+              digest=$(jq -r '.config.digest' <<< "${digest}");
+            fi
+          fi
           image_info=$(curl -sL \
             --header "Authorization: Bearer ${token}" \
             "https://ghcr.io/v2/${image}/blobs/${digest}")
@@ -92,7 +109,7 @@ jobs:
             else
               printf "\n## Trigger new build\n\n" >> $GITHUB_STEP_SUMMARY
               echo "New version \`${EXT_RELEASE}\` found; old version was \`${IMAGE_VERSION}\`. Triggering new build" >> $GITHUB_STEP_SUMMARY
-              if "${artifacts_found}" == "true" ]]; then
+              if [[ "${artifacts_found}" == "true" ]]; then
                 echo "All artifacts seem to be uploaded." >> $GITHUB_STEP_SUMMARY
               fi
               response=$(curl -iX POST \
diff --git a/.github/workflows/package_trigger_scheduler.yml b/.github/workflows/package_trigger_scheduler.yml
index 1591155..ee7b6b7 100644
--- a/.github/workflows/package_trigger_scheduler.yml
+++ b/.github/workflows/package_trigger_scheduler.yml
@@ -27,9 +27,18 @@ jobs:
             fi
             printf "\n## Evaluating \`%s\`\n\n" ${br} >> $GITHUB_STEP_SUMMARY
             JENKINS_VARS=$(curl -sX GET https://raw.githubusercontent.com/linuxserver/docker-readarr/${br}/jenkins-vars.yml)
-            if [[ "${br}" == $(yq -r '.ls_branch' <<< "${JENKINS_VARS}") ]]; then
+            if ! curl -sfX GET https://raw.githubusercontent.com/linuxserver/docker-readarr/${br}/Jenkinsfile >/dev/null 2>&1; then
+              echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
+              echo "> No Jenkinsfile found. Branch is either deprecated or is an early dev branch." >> $GITHUB_STEP_SUMMARY
+              skipped_branches="${skipped_branches}${br} "
+            elif [[ "${br}" == $(yq -r '.ls_branch' <<< "${JENKINS_VARS}") ]]; then
               echo "Branch appears to be live; checking workflow." >> $GITHUB_STEP_SUMMARY
-              if [[ $(yq -r '.skip_package_check' <<< "${JENKINS_VARS}") == "true" ]]; then
+              README_VARS=$(curl -sX GET https://raw.githubusercontent.com/linuxserver/docker-readarr/${br}/readme-vars.yml)
+              if [[ $(yq -r '.project_deprecation_status' <<< "${README_VARS}") == "true" ]]; then
+                echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
+                echo "> Branch appears to be deprecated; skipping trigger." >> $GITHUB_STEP_SUMMARY
+                skipped_branches="${skipped_branches}${br} "
+              elif [[ $(yq -r '.skip_package_check' <<< "${JENKINS_VARS}") == "true" ]]; then
                 echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
                 echo "> Skipping branch ${br} due to \`skip_package_check\` being set in \`jenkins-vars.yml\`." >> $GITHUB_STEP_SUMMARY
                 skipped_branches="${skipped_branches}${br} "
@@ -37,7 +46,7 @@ jobs:
                 echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
                 echo "> Github organizational variable \`SKIP_PACKAGE_TRIGGER\` contains \`readarr_${br}\`; skipping trigger." >> $GITHUB_STEP_SUMMARY
                 skipped_branches="${skipped_branches}${br} "
-              elif [ $(curl -s https://ci.linuxserver.io/job/Docker-Pipeline-Builders/job/docker-readarr/job/${br}/lastBuild/api/json | jq -r '.building') == "true" ]; then
+              elif [ $(curl -s https://ci.linuxserver.io/job/Docker-Pipeline-Builders/job/docker-readarr/job/${br}/lastBuild/api/json | jq -r '.building' 2>/dev/null) == "true" ]; then
                 echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
                 echo "> There already seems to be an active build on Jenkins; skipping package trigger for ${br}" >> $GITHUB_STEP_SUMMARY
                 skipped_branches="${skipped_branches}${br} "
@@ -49,6 +58,11 @@ jobs:
                 response=$(curl -iX POST \
                   https://ci.linuxserver.io/job/Docker-Pipeline-Builders/job/docker-readarr/job/${br}/buildWithParameters?PACKAGE_CHECK=true \
                   --user ${{ secrets.JENKINS_USER }}:${{ secrets.JENKINS_TOKEN }} | grep -i location | sed "s|^[L|l]ocation: \(.*\)|\1|")
+                if [[ -z "${response}" ]]; then
+                  echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
+                  echo "> Jenkins build could not be triggered. Skipping branch."
+                  continue
+                fi
                 echo "Jenkins [job queue url](${response%$'\r'})" >> $GITHUB_STEP_SUMMARY
                 echo "Sleeping 10 seconds until job starts" >> $GITHUB_STEP_SUMMARY
                 sleep 10
@@ -56,11 +70,14 @@ jobs:
                 buildurl="${buildurl%$'\r'}"
                 echo "Jenkins job [build url](${buildurl})" >> $GITHUB_STEP_SUMMARY
                 echo "Attempting to change the Jenkins job description" >> $GITHUB_STEP_SUMMARY
-                curl -iX POST \
+                if ! curl -ifX POST \
                   "${buildurl}submitDescription" \
                   --user ${{ secrets.JENKINS_USER }}:${{ secrets.JENKINS_TOKEN }} \
                   --data-urlencode "description=GHA package trigger https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}" \
-                  --data-urlencode "Submit=Submit"
+                  --data-urlencode "Submit=Submit"; then
+                  echo "> [!WARNING]" >> $GITHUB_STEP_SUMMARY
+                  echo "> Unable to change the Jenkins job description."
+                fi
                 sleep 20
               fi
             else
diff --git a/Dockerfile b/Dockerfile
index d97261b..85cf97e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-FROM ghcr.io/linuxserver/baseimage-alpine:3.20
+FROM ghcr.io/linuxserver/baseimage-alpine:3.21
 
 # set version label
 ARG BUILD_DATE
diff --git a/Dockerfile.aarch64 b/Dockerfile.aarch64
index 6fdeedc..a4e7e45 100644
--- a/Dockerfile.aarch64
+++ b/Dockerfile.aarch64
@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-FROM ghcr.io/linuxserver/baseimage-alpine:arm64v8-3.20
+FROM ghcr.io/linuxserver/baseimage-alpine:arm64v8-3.21
 
 # set version label
 ARG BUILD_DATE
diff --git a/Jenkinsfile b/Jenkinsfile
index ba7caed..f167faa 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -32,7 +32,7 @@ pipeline {
     CI_WEB='true'
     CI_PORT='8787'
     CI_SSL='false'
-    CI_DELAY='120'
+    CI_DELAY='240'
     CI_DOCKERENV=''
     CI_AUTH=''
     CI_WEBPATH='/system/status'
@@ -575,7 +575,7 @@ pipeline {
           --label \"org.opencontainers.image.title=Readarr\" \
           --label \"org.opencontainers.image.description=[Readarr](https://github.com/Readarr/Readarr) - Book Manager and Automation (Sonarr for Ebooks)  \" \
           --no-cache --pull -t ${IMAGE}:${META_TAG} --platform=linux/amd64 \
-          --provenance=false --sbom=false --builder=container --load \
+          --provenance=true --sbom=true --builder=container --load \
           --build-arg ${BUILD_VERSION_ARG}=${EXT_RELEASE} --build-arg VERSION=\"${VERSION_TAG}\" --build-arg BUILD_DATE=${GITHUB_DATE} ."
         sh '''#! /bin/bash
               set -e
@@ -604,7 +604,9 @@ pipeline {
                       for i in "${CACHE[@]}"; do
                         docker push ${i}:amd64-${COMMIT_SHA}-${BUILD_NUMBER} &
                       done
-                      wait
+                      for p in $(jobs -p); do
+                        wait "$p" || { echo "job $p failed" >&2; exit 1; }
+                      done
                     fi
                 '''
           }
@@ -639,7 +641,7 @@ pipeline {
               --label \"org.opencontainers.image.title=Readarr\" \
               --label \"org.opencontainers.image.description=[Readarr](https://github.com/Readarr/Readarr) - Book Manager and Automation (Sonarr for Ebooks)  \" \
               --no-cache --pull -t ${IMAGE}:amd64-${META_TAG} --platform=linux/amd64 \
-              --provenance=false --sbom=false --builder=container --load \
+              --provenance=true --sbom=true --builder=container --load \
               --build-arg ${BUILD_VERSION_ARG}=${EXT_RELEASE} --build-arg VERSION=\"${VERSION_TAG}\" --build-arg BUILD_DATE=${GITHUB_DATE} ."
             sh '''#! /bin/bash
                   set -e
@@ -668,7 +670,9 @@ pipeline {
                           for i in "${CACHE[@]}"; do
                             docker push ${i}:amd64-${COMMIT_SHA}-${BUILD_NUMBER} &
                           done
-                          wait
+                          for p in $(jobs -p); do
+                            wait "$p" || { echo "job $p failed" >&2; exit 1; }
+                          done
                         fi
                     '''
               }
@@ -696,7 +700,7 @@ pipeline {
               --label \"org.opencontainers.image.title=Readarr\" \
               --label \"org.opencontainers.image.description=[Readarr](https://github.com/Readarr/Readarr) - Book Manager and Automation (Sonarr for Ebooks)  \" \
               --no-cache --pull -f Dockerfile.aarch64 -t ${IMAGE}:arm64v8-${META_TAG} --platform=linux/arm64 \
-              --provenance=false --sbom=false --builder=container --load \
+              --provenance=true --sbom=true --builder=container --load \
               --build-arg ${BUILD_VERSION_ARG}=${EXT_RELEASE} --build-arg VERSION=\"${VERSION_TAG}\" --build-arg BUILD_DATE=${GITHUB_DATE} ."
             sh '''#! /bin/bash
                   set -e
@@ -725,7 +729,9 @@ pipeline {
                           for i in "${CACHE[@]}"; do
                             docker push ${i}:arm64v8-${COMMIT_SHA}-${BUILD_NUMBER} &
                           done
-                          wait
+                          for p in $(jobs -p); do
+                            wait "$p" || { echo "job $p failed" >&2; exit 1; }
+                          done
                         fi
                     '''
               }
diff --git a/README.md b/README.md
index 9b06a1f..4ea418f 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,10 @@ The folks over at servarr.com wrote a good [write-up](https://wiki.servarr.com/d
 
 This image can be run with a read-only container filesystem. For details please [read the docs](https://docs.linuxserver.io/misc/read-only/).
 
+## Non-Root Operation
+
+This image can be run with a non-root user. For details please [read the docs](https://docs.linuxserver.io/misc/non-root/).
+
 ## Usage
 
 To help you get started creating a container from this image you can either use docker-compose or the docker cli.
@@ -141,6 +145,7 @@ Containers are configured using parameters passed at runtime (such as those abov
 | `-v /books` | Location of Book library on disk (See note in Application setup) |
 | `-v /downloads` | Location of download managers output directory (See note in Application setup) |
 | `--read-only=true` | Run container with a read-only filesystem. Please [read the docs](https://docs.linuxserver.io/misc/read-only/). |
+| `--user=1000:1000` | Run container with a non-root user. Please [read the docs](https://docs.linuxserver.io/misc/non-root/). |
 
 ## Environment variables from files (Docker secrets)
 
@@ -304,6 +309,7 @@ Once registered you can define the dockerfile to use with `-f Dockerfile.aarch64
 
 ## Versions
 
+* **20.12.24:** - Rebase to Alpine 3.21.
 * **25.05.24:** - Rebase to Alpine 3.20.
 * **20.03.24:** - Rebase to Alpine 3.19.
 * **06.06.23:** - Rebase develop to Alpine 3.18.
diff --git a/jenkins-vars.yml b/jenkins-vars.yml
index 3f75ffc..a2eda53 100644
--- a/jenkins-vars.yml
+++ b/jenkins-vars.yml
@@ -20,7 +20,7 @@ repo_vars:
   - CI_WEB='true'
   - CI_PORT='8787'
   - CI_SSL='false'
-  - CI_DELAY='120'
+  - CI_DELAY='240'
   - CI_DOCKERENV=''
   - CI_AUTH=''
   - CI_WEBPATH='/system/status'
diff --git a/readme-vars.yml b/readme-vars.yml
index 3e0ac83..6005d81 100644
--- a/readme-vars.yml
+++ b/readme-vars.yml
@@ -28,6 +28,7 @@ param_usage_include_ports: true
 param_ports:
   - {external_port: "8787", internal_port: "8787", port_desc: "The port for the Readarr web UI"}
 readonly_supported: true
+nonroot_supported: true
 # application setup block
 app_setup_block_enabled: true
 app_setup_block: |
@@ -85,6 +86,7 @@ init_diagram: |
   "readarr:develop" <- Base Images
 # changelog
 changelogs:
+  - {date: "20.12.24:", desc: "Rebase to Alpine 3.21."}
   - {date: "25.05.24:", desc: "Rebase to Alpine 3.20."}
   - {date: "20.03.24:", desc: "Rebase to Alpine 3.19."}
   - {date: "06.06.23:", desc: "Rebase develop to Alpine 3.18."}
diff --git a/root/etc/s6-overlay/s6-rc.d/init-readarr-config/run b/root/etc/s6-overlay/s6-rc.d/init-readarr-config/run
index 12adc03..bc8cb5d 100755
--- a/root/etc/s6-overlay/s6-rc.d/init-readarr-config/run
+++ b/root/etc/s6-overlay/s6-rc.d/init-readarr-config/run
@@ -3,7 +3,8 @@
 
 mkdir -p /run/readarr-temp
 
-# permissions
-lsiown -R abc:abc \
-    /config \
-    /run/readarr-temp
+if [[ -z ${LSIO_NON_ROOT_USER} ]]; then
+    lsiown -R abc:abc \
+        /config \
+        /run/readarr-temp
+fi
diff --git a/root/etc/s6-overlay/s6-rc.d/svc-readarr/run b/root/etc/s6-overlay/s6-rc.d/svc-readarr/run
index 44006a5..5c53374 100755
--- a/root/etc/s6-overlay/s6-rc.d/svc-readarr/run
+++ b/root/etc/s6-overlay/s6-rc.d/svc-readarr/run
@@ -1,7 +1,14 @@
 #!/usr/bin/with-contenv bash
 # shellcheck shell=bash
 
-exec \
-    s6-notifyoncheck -d -n 300 -w 1000 \
-        cd /app/readarr/bin s6-setuidgid abc /app/readarr/bin/Readarr \
-        -nobrowser -data=/config
+if [[ -z ${LSIO_NON_ROOT_USER} ]]; then
+    exec \
+        s6-notifyoncheck -d -n 300 -w 1000 \
+            cd /app/readarr/bin s6-setuidgid abc /app/readarr/bin/Readarr \
+            -nobrowser -data=/config
+else
+    exec \
+        s6-notifyoncheck -d -n 300 -w 1000 \
+            cd /app/readarr/bin /app/readarr/bin/Readarr \
+            -nobrowser -data=/config
+fi