diff --git a/setup/start/sudoers b/setup/start/sudoers
index 1770141af..f88936a05 100644
--- a/setup/start/sudoers
+++ b/setup/start/sudoers
@@ -7,6 +7,9 @@ yellowtent ALL=(root) NOPASSWD: /home/yellowtent/box/src/scripts/rmvolume.sh
 Defaults!/home/yellowtent/box/src/scripts/rmredis.sh env_keep="HOME BOX_ENV"
 yellowtent ALL=(root) NOPASSWD: /home/yellowtent/box/src/scripts/rmredis.sh
 
+Defaults!/home/yellowtent/box/src/scripts/rmaddon.sh env_keep="HOME BOX_ENV"
+yellowtent ALL=(root) NOPASSWD: /home/yellowtent/box/src/scripts/rmaddon.sh
+
 Defaults!/home/yellowtent/box/src/scripts/reloadnginx.sh env_keep="HOME BOX_ENV"
 yellowtent ALL=(root) NOPASSWD: /home/yellowtent/box/src/scripts/reloadnginx.sh
 
diff --git a/src/addons.js b/src/addons.js
index 05ca7f1d6..4ffda1225 100644
--- a/src/addons.js
+++ b/src/addons.js
@@ -141,7 +141,7 @@ var KNOWN_ADDONS = {
 function debugApp(app, args) {
     assert(typeof app === 'object');
 
-    debug(app.fqdn + ' ' + util.format.apply(util, Array.prototype.slice.call(arguments, 1)));
+    debug((app.fqdn || app.location) + ' ' + util.format.apply(util, Array.prototype.slice.call(arguments, 1)));
 }
 
 function getAddonDetails(containerName, tokenEnvName, callback) {
@@ -291,8 +291,14 @@ function importDatabase(addon, callback) {
         if (error) return callback(error);
 
         async.eachSeries(apps, function iterator (app, iteratorCallback) {
-            debug(`importDatabase: Importing app ${app.id}`)
-            KNOWN_ADDONS[addon].restore(app, addon, iteratorCallback);
+            if (!(addon in app.manifest.addons)) return iteratorCallback(); // app doesn't use the addon
+
+            debug(`importDatabase: Importing addon ${addon} of app ${app.id}`);
+
+            async.series([
+                KNOWN_ADDONS[addon].setup.bind(null, app, app.manifest.addons[addon]),
+                KNOWN_ADDONS[addon].restore.bind(null, app, app.manifest.addons[addon])
+            ], iteratorCallback);
         }, callback);
     });
 }
diff --git a/src/platform.js b/src/platform.js
index c7cb9f7cb..2a9c5c53d 100644
--- a/src/platform.js
+++ b/src/platform.js
@@ -19,6 +19,7 @@ var addons = require('./addons.js'),
     locker = require('./locker.js'),
     mail = require('./mail.js'),
     os = require('os'),
+    path = require('path'),
     paths = require('./paths.js'),
     reverseProxy = require('./reverseproxy.js'),
     safe = require('safetydance'),
@@ -30,6 +31,8 @@ var addons = require('./addons.js'),
 
 var gPlatformReadyTimer = null;
 
+const RMADDON_CMD = path.join(__dirname, 'scripts/rmaddon.sh');
+
 var NOOP_CALLBACK = function (error) { if (error) debug(error); };
 
 function start(callback) {
@@ -176,6 +179,20 @@ function startGraphite(callback) {
     callback();
 }
 
+function parseImageTag(tag) {
+    let repository = tag.split(':', 1)[0];
+    let version = tag.substr(repository.length + 1).split('@', 1)[0];
+    let digest = tag.substr(repository.length + 1 + version.length + 1).split(':', 2)[1];
+
+    return { repository, version: semver.parse(version), digest };
+}
+
+function requiresUpgrade(existingTag, currentTag) {
+    let etag = parseImageTag(existingTag), ctag = parseImageTag(currentTag);
+
+    return etag.version.major !== ctag.version.major;
+}
+
 function startMysql(existingInfra, callback) {
     assert.strictEqual(typeof existingInfra, 'object');
     assert.strictEqual(typeof callback, 'function');
@@ -186,6 +203,13 @@ function startMysql(existingInfra, callback) {
     const cloudronToken = hat(8 * 128);
     const memoryLimit = (1 + Math.round(os.totalmem()/(1024*1024*1024)/4)) * 256;
 
+    const upgrading = existingInfra.version !== 'none' && requiresUpgrade(existingInfra.images.mysql.tag, tag);
+
+    if (upgrading) {
+        debug('startMysql: mysql will be upgraded');
+        shell.sudoSync('startMysql', `${RMADDON_CMD} mysql`);
+    }
+
     const cmd = `docker run --restart=always -d --name="mysql" \
                 --net cloudron \
                 --net-alias mysql \
@@ -205,7 +229,12 @@ function startMysql(existingInfra, callback) {
 
     shell.execSync('startMysql', cmd);
 
-    addons.waitForAddon('mysql', 'CLOUDRON_MYSQL_TOKEN', callback);
+    addons.waitForAddon('mysql', 'CLOUDRON_MYSQL_TOKEN', function (error) {
+        if (error) return callback(error);
+        if (!upgrading) return callback(null);
+
+        addons.importDatabase('mysql', callback);
+    });
 }
 
 function startPostgresql(existingInfra, callback) {
@@ -218,6 +247,13 @@ function startPostgresql(existingInfra, callback) {
     const cloudronToken = hat(8 * 128);
     const memoryLimit = (1 + Math.round(os.totalmem()/(1024*1024*1024)/4)) * 256;
 
+    const upgrading = existingInfra.version !== 'none' && requiresUpgrade(existingInfra.images.postgresql.tag, tag);
+
+    if (upgrading) {
+        debug('startPostgresql: postgresql will be upgraded');
+        shell.sudoSync('startPostgresql', `${RMADDON_CMD} postgresql`);
+    }
+
     const cmd = `docker run --restart=always -d --name="postgresql" \
                 --net cloudron \
                 --net-alias postgresql \
@@ -236,7 +272,12 @@ function startPostgresql(existingInfra, callback) {
 
     shell.execSync('startPostgresql', cmd);
 
-    addons.waitForAddon('postgresql', 'CLOUDRON_POSTGRESQL_TOKEN', callback);
+    addons.waitForAddon('postgresql', 'CLOUDRON_POSTGRESQL_TOKEN', function (error) {
+        if (error) return callback(error);
+        if (!upgrading) return callback(null);
+
+        addons.importDatabase('postgresql', callback);
+    });
 }
 
 function startMongodb(existingInfra, callback) {
@@ -249,6 +290,14 @@ function startMongodb(existingInfra, callback) {
     const cloudronToken = hat(8 * 128);
     const memoryLimit = (1 + Math.round(os.totalmem()/(1024*1024*1024)/4)) * 200;
 
+
+    const upgrading = existingInfra.version !== 'none' && requiresUpgrade(existingInfra.images.mongodb.tag, tag);
+
+    if (upgrading) {
+        debug('startMongodb: mongodb will be upgraded');
+        shell.sudoSync('startMongodb', `${RMADDON_CMD} mongodb`);
+    }
+
     const cmd = `docker run --restart=always -d --name="mongodb" \
                 --net cloudron \
                 --net-alias mongodb \
@@ -267,7 +316,12 @@ function startMongodb(existingInfra, callback) {
 
     shell.execSync('startMongodb', cmd);
 
-    addons.waitForAddon('mongodb', 'CLOUDRON_MONGODB_TOKEN', callback);
+    addons.waitForAddon('mongodb', 'CLOUDRON_MONGODB_TOKEN', function (error) {
+        if (error) return callback(error);
+        if (!upgrading) return callback(null);
+
+        addons.importDatabase('mongodb', callback);
+    });
 }
 
 function startAddons(existingInfra, callback) {
diff --git a/src/scripts/rmaddon.sh b/src/scripts/rmaddon.sh
new file mode 100755
index 000000000..f500e3143
--- /dev/null
+++ b/src/scripts/rmaddon.sh
@@ -0,0 +1,37 @@
+#!/bin/bash
+
+set -eu -o pipefail
+
+if [[ ${EUID} -ne 0 ]]; then
+    echo "This script should be run as root." > /dev/stderr
+    exit 1
+fi
+
+if [[ $# -eq 0 ]]; then
+    echo "No arguments supplied"
+    exit 1
+fi
+
+if [[ "$1" == "--check" ]]; then
+    echo "OK"
+    exit 0
+fi
+
+addon="$1"
+appid="${2:-}"   # only valid for redis
+if [[ "${addon}" != "postgresql" && "${addon}" != "mysql" && "${addon}" != "mongodb" && "${addon}" != "redis" ]]; then
+    echo "${addon} must be postgresql/mysql/mongodb/redis"
+    exit 1
+fi
+
+if [[ "${BOX_ENV}" == "cloudron" ]]; then
+    readonly addon_dir="${HOME}/platformdata/${addon}"
+else
+    readonly addon_dir="${HOME}/.cloudron_test/platformdata/${addon}"
+fi
+
+rm -rf "${addon_dir}"
+if [[ "${addon}" != "redis" ]]; then
+    mkdir "${addon_dir}"
+fi
+
diff --git a/src/test/checkInstall b/src/test/checkInstall
index 8db93c482..f03df8c43 100755
--- a/src/test/checkInstall
+++ b/src/test/checkInstall
@@ -11,6 +11,7 @@ sudo -k || sudo --reset-timestamp
 # checks if all scripts are sudo access
 scripts=("${SOURCE_DIR}/src/scripts/rmvolume.sh" \
          "${SOURCE_DIR}/src/scripts/rmredis.sh" \
+         "${SOURCE_DIR}/src/scripts/rmaddon.sh" \
          "${SOURCE_DIR}/src/scripts/reloadnginx.sh" \
          "${SOURCE_DIR}/src/scripts/reboot.sh" \
          "${SOURCE_DIR}/src/scripts/update.sh" \