diff --git a/.github/workflows/markdownlint.yml b/.github/workflows/markdownlint.yml
index 72115e3..c75fbe5 100644
--- a/.github/workflows/markdownlint.yml
+++ b/.github/workflows/markdownlint.yml
@@ -20,4 +20,4 @@ jobs:
       - name: Pull markdownlint/markdownlint:latest Image
         run: docker pull markdownlint/markdownlint:latest
       - name: Run markdownlint against *.md files
-        run: docker run --rm -i -v "$(pwd)":/workdir --workdir /workdir markdownlint/markdownlint:latest --rules ~MD013,~MD033,~MD026,~MD002,~MD022 $(find . -type f -iname '*.md' | grep -v '/.git/')
+        run: docker run --rm -i -v "$(pwd)":/workdir --workdir /workdir markdownlint/markdownlint:latest --rules ~MD013,~MD033,~MD026,~MD002,~MD022,~MD029,~MD034,~MD056 $(find . -type f -iname '*.md' | grep -v '/.git/')
diff --git a/.markdownlint.yaml b/.markdownlint.yaml
index 151ee39..5dec587 100644
--- a/.markdownlint.yaml
+++ b/.markdownlint.yaml
@@ -1,4 +1,7 @@
 {
     "MD013": false,
-    "MD033": false
+    "MD033": false,
+    "MD029": false,
+    "MD034": false,
+    "MD056": false
 }
\ No newline at end of file
diff --git a/Dockerfile.build-aiscatcher b/Dockerfile.build-aiscatcher
index 71f47d3..f096ccc 100644
--- a/Dockerfile.build-aiscatcher
+++ b/Dockerfile.build-aiscatcher
@@ -1,9 +1,9 @@
-FROM debian:bullseye-slim AS build
+FROM debian:bookwork-slim AS build
 
 RUN set -x && \
     apt-get update -y && \
     apt-get upgrade -y && \
-    apt-get install -q -o Dpkg::Options::="--force-confnew" -y \
+    apt-get install -q -o Dpkg::Options::="--force-confnew" --no-install-recommends -y \
         git make gcc g++ cmake pkg-config librtlsdr-dev libairspy-dev libhackrf-dev libairspyhf-dev libzmq3-dev libsoxr-dev libcurl4-openssl-dev zlib1g-dev && \
     git clone --depth=1 -b develop --single-branch https://github.com/jvde-github/AIS-catcher.git /root/AIS-catcher && \
     cd /root/AIS-catcher && \
diff --git a/config-examples/README.md b/config-examples/README.md
index 35172ac..2243609 100644
--- a/config-examples/README.md
+++ b/config-examples/README.md
@@ -89,7 +89,7 @@ Make the changes based on the description below, and once you are done, you can
 | `VA_DISCORD_AVATAR_URL` | Link to a URL that contains your avatar / picture |
 | `VA_DISCORD_WEBHOOKS` | Webhook(s) for Discord notifications. If you have multiple channels your want to notify to, you can comma-separate them. We prefilled this field with one for our special [`#Vessel-Alerts` Discord Channel](https://discord.gg/UMgZMc2AGp) |
 | `VA_SCREENSHOT_URL` | `http://ais-screenshot:5042` |
-| `BACKUP_RETENTION_TIME` | Time (in days) to keep backups of `aiscatcher.bin` and plugins. Note - this only affects the backups of these files and not the active `aiscatcher.bin` or active plugins | `30` (days) |
+| `BACKUP_RETENTION_TIME` | Time (in days) to keep backups of `aiscatcher.bin` and plugins. Note - this only affects the backups of these files and not the active `aiscatcher.bin` or active plugins. Default: `30` (days) |
 
 ## Starting your AIS Feeder
 
diff --git a/rootfs/scripts/update-plugins b/rootfs/scripts/update-plugins
index ccb0424..f424aeb 100755
--- a/rootfs/scripts/update-plugins
+++ b/rootfs/scripts/update-plugins
@@ -76,7 +76,7 @@ then
   for file in /tmp/AIS-catcher/plugins/*
   do
     file="${file##*/}"
-    if [[  f /data/plugins/${file} ]] && ! diff "${file}" "/data/plugins/${file}" >/dev/null 2>&1
+    if [[ -f /data/plugins/${file} ]] && ! diff "${file}" "/data/plugins/${file}" >/dev/null 2>&1
     then
       # Copy plugin file if it's newer but leave a backup in place
       cp --backup=numbered -u "/tmp/AIS-catcher/plugins/${file}" "/data/plugins/${file}"