diff --git a/build.sh b/build.sh
index 2137e51..5b0c704 100755
--- a/build.sh
+++ b/build.sh
@@ -2,12 +2,25 @@
 
 TAG="1.5-$(date +%Y%m%d)"
 
-find . -name Dockerfile | while read i; do
-    dir=$(dirname $i)
-    pushd ${dir} >/dev/null
-    image="genunix/mailu-$(basename $dir):${TAG}"
+build() {
+    image=$1
     echo "[INFO] Building ${image}"
     docker build -t ${image} .
     docker push ${image}
+}
+
+if [ -z "$1" ]; then
+    find . -name Dockerfile | while read i; do
+        dir=$(dirname $i)
+        pushd ${dir} >/dev/null
+        image="genunix/mailu-$(basename $dir):${TAG}"
+        build ${image}
+        popd >/dev/null
+    done
+else
+    dir=$(basename $1)
+    image="genunix/mailu-$(basename $dir):${TAG}"
+    pushd "$1" >/dev/null
+    build "$image"
     popd >/dev/null
-done
+fi
diff --git a/core/admin/Dockerfile b/core/admin/Dockerfile
index cfc8ac8..6e96f73 100644
--- a/core/admin/Dockerfile
+++ b/core/admin/Dockerfile
@@ -5,7 +5,7 @@ WORKDIR /app
 
 COPY requirements-prod.txt requirements.txt
 RUN apk add --no-cache openssl \
- && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python-dev build-base \
+ && apk add --no-cache --virtual build-dep openssl-dev libffi-dev python3-dev build-base \
  && pip install -r requirements.txt \
  && apk del build-dep
 
diff --git a/core/dovecot/Dockerfile b/core/dovecot/Dockerfile
index 843171a..03eb282 100644
--- a/core/dovecot/Dockerfile
+++ b/core/dovecot/Dockerfile
@@ -2,8 +2,8 @@ FROM alpine:3.13
 
 RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
  && apk add --no-cache \
-     dovecot dovecot-sqlite dovecot-pigeonhole-plugin dovecot-pigeonhole-plugin-extdata \
-     rspamd-client@testing python py-jinja2
+     dovecot dovecot-sqlite dovecot-pigeonhole-plugin \
+     rspamd-client python3 py3-jinja2
 
 COPY conf /conf
 COPY sieve /var/lib/dovecot
diff --git a/core/postfix/start.py b/core/postfix/start.py
index f6068ad..2402362 100755
--- a/core/postfix/start.py
+++ b/core/postfix/start.py
@@ -5,7 +5,7 @@ import os
 import socket
 import glob
 import shutil
-	
+
 convert = lambda src, dst: open(dst, "w").write(jinja2.Template(open(src).read()).render(**os.environ))
 
 # Actual startup script
@@ -33,6 +33,6 @@ convert("/conf/rsyslog.conf", "/etc/rsyslog.conf")
 # Run postfix
 if os.path.exists("/var/run/rsyslogd.pid"):
     os.remove("/var/run/rsyslogd.pid")
-os.system("/usr/lib/postfix/post-install meta_directory=/etc/postfix create-missing")
-os.system("/usr/lib/postfix/master &")
+os.system("/usr/libexec/postfix/post-install meta_directory=/etc/postfix create-missing")
+os.system("/usr/sbin/postfix start")
 os.execv("/usr/sbin/rsyslogd", ["rsyslogd", "-n"])