diff --git a/Containerfile b/Containerfile
index a5a3487..8debbfd 100644
--- a/Containerfile
+++ b/Containerfile
@@ -1,11 +1,93 @@
-FROM docker.io/thallian/confd-env:3.20-3.1.6.2
+FROM docker.io/alpine:3.19 as builder
 
 RUN apk --no-cache add \
+  rpcgen \
+  g++ \
+  make \
+  openssl \
+  openssl-dev \
+  lua5.1-dev \
+  libsodium-dev \
+  linux-pam-dev \
+  zlib-dev \
+  bzip2-dev \
+  xz-dev \
+  lz4-dev \
+  icu-dev \
+  inotify-tools-dev
+
+ENV SHA256_SUM_DOVECOT=05b11093a71c237c2ef309ad587510721cc93bbee6828251549fc1586c36502d
+ENV DOVECOT_FILENAME=dovecot-2.3.21.tar.gz
+RUN wget https://www.dovecot.org/releases/2.3/$DOVECOT_FILENAME
+RUN echo "$SHA256_SUM_DOVECOT  $DOVECOT_FILENAME" | sha256sum -c - || exit 1
+RUN mkdir /tmp/dovecot
+RUN tar xzf $DOVECOT_FILENAME -C /tmp/dovecot --strip 1
+
+ENV SHA256_SUM_PIGEONHOLE=1ca71d2659076712058a72030288f150b2b076b0306453471c5261498d3ded27
+ENV PIGEONHOLE_FILENAME=dovecot-2.3-pigeonhole-0.5.21.tar.gz
+RUN wget https://pigeonhole.dovecot.org/releases/2.3/$PIGEONHOLE_FILENAME
+RUN echo "$SHA256_SUM_PIGEONHOLE  $PIGEONHOLE_FILENAME" | sha256sum -c - || exit 1
+RUN mkdir /tmp/pigeonhole
+RUN tar xzf $PIGEONHOLE_FILENAME -C /tmp/pigeonhole --strip 1
+
+RUN cd /tmp/dovecot && \
+  ./configure --prefix '' \
+  --with-notify=inotify \
+  --with-lua \
+  --with-zlib \
+  --with-bzlib \
+  --with-pam \
+  --with-ssl=openssl \
+  --with-sodium \
+  --without-sql \
+  --with-lzma \
+  --with-lz4 \
+  --with-icu \
+  --without-shadow \
+  --with-ssldir=/etc/ssl/mail \
+  --with-rundir=/run/dovecot \
+  --disable-static && \
+  make && \
+  make install
+
+RUN cd /tmp/pigeonhole && \
+  ./configure --prefix '' \
+  --with-dovecot=/lib/dovecot \
+  --disable-static && \
+  make && make install
+
+FROM docker.io/thallian/confd-env:3.19-3.1.6.2
+
+COPY --from=builder /lib/dovecot/ /lib/dovecot/
+COPY --from=builder /libexec/dovecot/ /libexec/dovecot/
+COPY --from=builder /bin/doveadm /bin/doveadm
+COPY --from=builder /bin/doveconf /bin/doveconf
+COPY --from=builder /bin/dsync /bin/dsync
+COPY --from=builder /sbin/dovecot /sbin/dovecot
+COPY --from=builder /bin/sieve* /bin/
+
+RUN apk --no-cache add \
+  libsodium \
+  libbz2 \
+  zlib \
+  xz-libs \
+  lz4-libs \
+  lz4 \
+  linux-pam \
+  openssl \
   ssmtp \
-  dovecot \
-  dovecot-pgsql \
-  dovecot-lmtpd \
-  dovecot-pigeonhole-plugin
+  ca-certificates \
+  lua5.1-libs \
+  lua5.1-rapidjson \
+  curl \
+  inotify-tools \
+  libssl3
+
+RUN addgroup -g 150 dovecot
+RUN adduser -u 140 -h /dev/null -H -s /sbin/nologin -D -G dovecot dovecot
+
+RUN addgroup -g 151 dovenull
+RUN adduser -u 141 -h /dev/null -H -s /sbin/nologin -D -G dovenull dovenull
 
 RUN addgroup -g 2222 access
 RUN addgroup dovecot access
diff --git a/README.md b/README.md
index 2b4c0a4..4f4855e 100644
--- a/README.md
+++ b/README.md
@@ -1,101 +1,75 @@
-[Dovecot](http://www.dovecot.org/) with imap, starttls, oauth2 proxy auth and
-sieve rules.
+[Dovecot](http://www.dovecot.org/) with imap, starttls, oauth2 proxy auth and sieve rules.
 
-Uses [SSMTP](https://packages.debian.org/stable/mail/ssmtp) to send mails (for
-example if you have a redirect sieve rule).
+Uses [SSMTP](https://packages.debian.org/stable/mail/ssmtp) to send mails (for example if you have a redirect sieve rule).
 
-Reuses the same database schema as the {postfix container](/container/postfix).
 
 # Volumes
-
 - `/var/lib/vmail/mail`
 
 # Environment Variables
-
 ## HOSTNAME
-
 Fully qualified name of the mail host.
 
 ## GRANT_URL
-
 OAuth2 url for token grants (password grant type).
 
 ## INTROSPECTION_URL
+OAuth2 url for token information.
 
-OAuth2 url for token information. Must include client id and client secret in
-basic auth format.
+## USER_URL
+OAuth2 url for getting available users, the username will be appended to the end.
 
-## TOKENINFO_URL
+## TOKENINFO_URL 
+OAuth2 url for requestion information about a token.
 
-OAuth2 url for requestion information about a token. Must include client id and
-client secret in basic auth format.
+## CLIENT_ID
+Id of the OAuth2 application.
 
-## DB_HOST
+## CLIENT_SECRET
+Secret of the OAuth2 application.
 
-Postgre database host.
+## OAUTH_ADMIN_USER
+User with which to perform user lookups (does not have to be an admin, but needs enough rights for that).
 
-## DB_USER
-
-User to connect to the database.
-
-## DB_PW
-
-Password to use for the database user.
-
-## DB_NAME
-
-- default: email
-
-Name of the postgre database to connect to.
+## OAUTH_ADMIN_PASSWORD
+Password for the `OAUTH_ADMIN_USER`.
 
 ## SSMTP_MAIL_RELAY
-
 Hostname and port for the used smtp relay (for example `mail.example.com:587`).
 
 ## SSMTP_USER
-
 User to authenticate agains the smtp relay.
 
 ## SSMTP_PASSWORD
-
 Password to authenticate agains the smtp relay.
 
 ## SSMTP_AUTH_METHOD
-
 - default: LOGIN
 
 Which authentication mechanism to use for the smtp relay.
 
 ## SSMTP_USE_STARTTLS
-
 - default: yes
 
 Whether to use starttls for the smtp relay.
 
 ## ALLOWED_USERNAME_CHARS
-
-- default:
-  äöüabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
+- default: äöüabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
 
 List of characters allowed in a username.
 
 ## AUTH_MECHANISMS
-
 - default: plain
 
-Space seperated list of supported
-[authentication mechanisms](http://wiki2.dovecot.org/Authentication/Mechanisms).
+Space seperated list of supported [authentication mechanisms](http://wiki2.dovecot.org/Authentication/Mechanisms).
 
 ## SSL_MIN_PROTOCOL
-
 - default: TLSv1.2
 
 Ssl minimum protocol version.
 
 ## SSL_CIPHERLIST
-
-- default:
-  ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256
+- default: ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256
 
 Colon seperated list of supported ciphers (`!`disables a cipher).
 
@@ -103,17 +77,14 @@ Go [here](https://www.openssl.org/docs/manmaster/man1/ciphers.html) for a list
 of ciphers.
 
 ## IMAP_MAX_USER_CONNECTIONS
-
 - default: 10
 
 Maximum number of connections from the same user + ip.
 
 # Ports
-
 - 143
 
 # Capabilities
-
 - CHOWN
 - DAC_OVERRIDE
 - FOWNER
diff --git a/rootfs/etc/confd/conf.d/dovecot-sql.userdb.ext.toml b/rootfs/etc/confd/conf.d/dovecot-sql.userdb.ext.toml
deleted file mode 100644
index ba1646d..0000000
--- a/rootfs/etc/confd/conf.d/dovecot-sql.userdb.ext.toml
+++ /dev/null
@@ -1,3 +0,0 @@
-[template]
-src = "dovecot-sql.userdb.conf.ext.tmpl"
-dest = "/etc/dovecot/dovecot-sql.userdb.conf.ext"
diff --git a/rootfs/etc/confd/conf.d/oauth2-userdb.lua.toml b/rootfs/etc/confd/conf.d/oauth2-userdb.lua.toml
new file mode 100644
index 0000000..cfb53ac
--- /dev/null
+++ b/rootfs/etc/confd/conf.d/oauth2-userdb.lua.toml
@@ -0,0 +1,3 @@
+[template]
+src = "oauth2-userdb.lua.tmpl"
+dest = "/etc/dovecot/oauth2-userdb.lua"
diff --git a/rootfs/etc/confd/templates/10-auth.conf.tmpl b/rootfs/etc/confd/templates/10-auth.conf.tmpl
index 8d99a1f..498385f 100644
--- a/rootfs/etc/confd/templates/10-auth.conf.tmpl
+++ b/rootfs/etc/confd/templates/10-auth.conf.tmpl
@@ -1,5 +1,4 @@
 auth_username_chars = {{getenv "ALLOWED_USERNAME_CHARS" "äöüabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@"}}
 auth_username_format ="%Ln"
 auth_mechanisms = {{getenv "AUTH_MECHANISMS" "plain login oauthbearer xoauth2"}}
-disable_plaintext_auth = no
 !include auth-oauth2.conf.ext
diff --git a/rootfs/etc/confd/templates/10-mail.conf.tmpl b/rootfs/etc/confd/templates/10-mail.conf.tmpl
index f15ee9c..3c064c3 100644
--- a/rootfs/etc/confd/templates/10-mail.conf.tmpl
+++ b/rootfs/etc/confd/templates/10-mail.conf.tmpl
@@ -23,4 +23,4 @@ namespace inbox {
   }
 }
 
-mail_plugin_dir = /usr/lib/dovecot
+mail_plugin_dir = /lib/dovecot
diff --git a/rootfs/etc/confd/templates/10-master.conf.tmpl b/rootfs/etc/confd/templates/10-master.conf.tmpl
index 391b1b4..928ebf7 100644
--- a/rootfs/etc/confd/templates/10-master.conf.tmpl
+++ b/rootfs/etc/confd/templates/10-master.conf.tmpl
@@ -2,11 +2,6 @@ service imap-login {
   inet_listener imap {
     port = 143
   }
-
-  inet_listener imaps {
-    port = 993
-    ssl = yes
-  }
 }
 
 service lmtp {
diff --git a/rootfs/etc/confd/templates/20-managesieve.conf.tmpl b/rootfs/etc/confd/templates/20-managesieve.conf.tmpl
index bfcce1c..ae406c3 100644
--- a/rootfs/etc/confd/templates/20-managesieve.conf.tmpl
+++ b/rootfs/etc/confd/templates/20-managesieve.conf.tmpl
@@ -5,6 +5,7 @@ protocols = $protocols sieve
 service managesieve-login {
   inet_listener sieve {
     port = 4190
+	  address = localhost
   }
 
   #inet_listener sieve_deprecated {
diff --git a/rootfs/etc/confd/templates/auth-oauth2.conf.ext.tmpl b/rootfs/etc/confd/templates/auth-oauth2.conf.ext.tmpl
index 5cfcf25..7d1a33a 100644
--- a/rootfs/etc/confd/templates/auth-oauth2.conf.ext.tmpl
+++ b/rootfs/etc/confd/templates/auth-oauth2.conf.ext.tmpl
@@ -11,7 +11,6 @@ passdb {
 }
 
 userdb {
-  driver = sql
-  args = /etc/dovecot/dovecot-sql.userdb.conf.ext
-  default_fields = uid=vmail gid=vmail home=/var/lib/vmail/mail/%u
+  driver = lua
+  args = file=/etc/dovecot/oauth2-userdb.lua blocking=yes
 }
diff --git a/rootfs/etc/confd/templates/dovecot-oauth2.plain.conf.ext.tmpl b/rootfs/etc/confd/templates/dovecot-oauth2.plain.conf.ext.tmpl
index 743a60e..419a169 100644
--- a/rootfs/etc/confd/templates/dovecot-oauth2.plain.conf.ext.tmpl
+++ b/rootfs/etc/confd/templates/dovecot-oauth2.plain.conf.ext.tmpl
@@ -1,4 +1,6 @@
 grant_url = {{ getenv "GRANT_URL" }}
+client_id = {{ getenv "CLIENT_ID" }}
+client_secret = {{ getenv "CLIENT_SECRET" }}
 introspection_url = {{ getenv "INTROSPECTION_URL" }}
 introspection_mode = {{ getenv "INTROSPECTION_MODE" "post" }}
 username_attribute = username
diff --git a/rootfs/etc/confd/templates/dovecot-oauth2.token.conf.ext.tmpl b/rootfs/etc/confd/templates/dovecot-oauth2.token.conf.ext.tmpl
index cc5b90e..4940f23 100644
--- a/rootfs/etc/confd/templates/dovecot-oauth2.token.conf.ext.tmpl
+++ b/rootfs/etc/confd/templates/dovecot-oauth2.token.conf.ext.tmpl
@@ -1,4 +1,6 @@
 grant_url = {{ getenv "GRANT_URL" }}
+client_id = {{ getenv "CLIENT_ID" }}
+client_secret = {{ getenv "CLIENT_SECRET" }}
 tokeninfo_url = {{ getenv "TOKENINFO_URL" }}
 introspection_url = {{ getenv "INTROSPECTION_URL" }}
 introspection_mode = {{ getenv "INTROSPECTION_MODE" "post" }}
@@ -6,3 +8,4 @@ username_attribute = username
 tls_ca_cert_file = /etc/ssl/certs/ca-certificates.crt
 use_grant_password = no
 pass_attrs = pass=%{oauth2:access_token}
+
diff --git a/rootfs/etc/confd/templates/dovecot-sql.userdb.conf.ext.tmpl b/rootfs/etc/confd/templates/dovecot-sql.userdb.conf.ext.tmpl
deleted file mode 100644
index e87aed7..0000000
--- a/rootfs/etc/confd/templates/dovecot-sql.userdb.conf.ext.tmpl
+++ /dev/null
@@ -1,3 +0,0 @@
-driver = pgsql
-connect = host={{ getenv "DB_HOST" }} dbname={{ getenv "DB_NAME" }} user={{ getenv "DB_USER" }} password={{ getenv "DB_PW" }}
-user_query = SELECT COUNT(email) as count FROM virtual_users WHERE email = '%n' HAVING COUNT(email) > 0;
diff --git a/rootfs/etc/confd/templates/oauth2-userdb.lua.tmpl b/rootfs/etc/confd/templates/oauth2-userdb.lua.tmpl
new file mode 100644
index 0000000..cc97b81
--- /dev/null
+++ b/rootfs/etc/confd/templates/oauth2-userdb.lua.tmpl
@@ -0,0 +1,44 @@
+local rapidjson = require('rapidjson')
+
+local clientId = "{{ getenv "CLIENT_ID" }}"
+local clientSecret = "{{ getenv "CLIENT_SECRET" }}"
+local username = "{{ getenv "OAUTH_ADMIN_USER" }}"
+local password = "{{ getenv "OAUTH_ADMIN_PASSWORD" }}"
+local tokenUrl = "{{ getenv "GRANT_URL" }}"
+local userUrl = "{{ getenv "USER_URL" }}"
+
+function os.capture(cmd, raw)
+  local f = assert(io.popen(cmd, 'r'))
+  local s = assert(f:read('*a'))
+  f:close()
+
+  return s
+end
+
+function auth_userdb_lookup(req)
+	local tokenCmd = "curl -L --silent -X POST -d \"grant_type=password\"" 
+	tokenCmd = tokenCmd .. " -d \"client_id=" .. clientId .. "\""
+	tokenCmd = tokenCmd .. " -d \"client_secret=" .. clientSecret .. "\""
+	tokenCmd = tokenCmd .. " -d \"username=" .. username .. "\""
+	tokenCmd = tokenCmd .. " -d \"password=" .. password .. "\""
+	tokenCmd = tokenCmd .. " \"" .. tokenUrl .. "\""
+
+	local tokenRaw = os.capture(tokenCmd)
+	local tokenJson = rapidjson.decode(tokenRaw)
+	local accessToken = tokenJson.access_token
+
+	local userCmd = "curl -L --silent -H \"Authorization: Bearer " .. accessToken .. "\" \"" .. userUrl .. req.username .. "\""
+	local userRaw = os.capture(userCmd)
+	local userJson = rapidjson.decode(userRaw)
+
+	if #userJson == 0 then
+		return dovecot.auth.USERDB_RESULT_USER_UNKNOWN, "no such user"
+	end
+
+	if userJson[1].username == req.username then
+		return dovecot.auth.USERDB_RESULT_OK, "uid=vmail gid=vmail home=/var/lib/vmail/mail/" .. req.username
+	end
+
+	return dovecot.auth.USERDB_RESULT_USER_UNKNOWN, "no such user"
+end
+