diff --git a/src/apps.js b/src/apps.js
index f0d2f37c9..5dd33bbc4 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -12,7 +12,6 @@ exports = module.exports = {
     update,
     setHealth,
     del,
-    delPortBinding,
 
     get,
     getByIpAddress,
@@ -192,7 +191,7 @@ const APPS_FIELDS_PREFIXED = [ 'apps.id', 'apps.appStoreId', 'apps.installationS
     'apps.enableMailbox', 'apps.mailboxDisplayName', 'apps.mailboxName', 'apps.mailboxDomain', 'apps.enableInbox', 'apps.inboxName', 'apps.inboxDomain',
     'apps.enableTurn', 'apps.enableRedis', 'apps.storageVolumeId', 'apps.storageVolumePrefix', 'apps.ts', 'apps.healthTime', '(apps.icon IS NOT NULL) AS hasIcon', '(apps.appStoreIcon IS NOT NULL) AS hasAppStoreIcon' ].join(',');
 
-// const PORT_BINDINGS_FIELDS = [ 'hostPort', 'type', 'environmentVariable', 'appId' ].join(',');
+// const PORT_BINDINGS_FIELDS = [ 'hostPort', 'type', 'environmentVariable', 'appId', 'count' ].join(',');
 const LOCATION_FIELDS = [ 'appId', 'subdomain', 'domain', 'type', 'certificateJson' ];
 
 const CHECKVOLUME_CMD = path.join(__dirname, 'scripts/checkvolume.sh');
@@ -652,13 +651,15 @@ function postProcess(result) {
     const hostPorts = result.hostPorts === null ? [ ] : result.hostPorts.split(',');
     const environmentVariables = result.environmentVariables === null ? [ ] : result.environmentVariables.split(',');
     const portTypes = result.portTypes === null ? [ ] : result.portTypes.split(',');
+    const portCounts = result.portCounts === null ? [ ] : result.portCounts.split(',');
 
     delete result.hostPorts;
     delete result.environmentVariables;
     delete result.portTypes;
+    delete result.portCounts;
 
     for (let i = 0; i < environmentVariables.length; i++) {
-        result.portBindings[environmentVariables[i]] = { hostPort: parseInt(hostPorts[i], 10), type: portTypes[i] };
+        result.portBindings[environmentVariables[i]] = { hostPort: parseInt(hostPorts[i], 10), type: portTypes[i], portCount: portCounts[i] };
     }
 
     assert(result.accessRestrictionJson === null || typeof result.accessRestrictionJson === 'string');
@@ -949,7 +950,6 @@ async function updateWithConstraints(id, app, constraints) {
     assert(!('checklist' in app) || typeof app.checklist === 'object');
     assert(!('env' in app) || typeof app.env === 'object');
 
-
     const queries = [ ];
 
     if ('portBindings' in app) {
@@ -1075,14 +1075,6 @@ async function del(id) {
     if (results[5].affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'App not found');
 }
 
-async function delPortBinding(hostPort, type) {
-    assert.strictEqual(typeof hostPort, 'number');
-    assert.strictEqual(typeof type, 'string');
-
-    const result = await database.query('DELETE FROM appPortBindings WHERE hostPort=? AND type=?', [ hostPort, type ]);
-    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'App not found');
-}
-
 async function clear() {
     await database.query('DELETE FROM locations');
     await database.query('DELETE FROM appPortBindings');
@@ -1092,11 +1084,11 @@ async function clear() {
 }
 
 // each query simply join apps table with another table by id. we then join the full result together
-const PB_QUERY = 'SELECT id, GROUP_CONCAT(CAST(appPortBindings.hostPort AS CHAR(6))) AS hostPorts, GROUP_CONCAT(appPortBindings.environmentVariable) AS environmentVariables, GROUP_CONCAT(appPortBindings.type) AS portTypes FROM apps LEFT JOIN appPortBindings ON apps.id = appPortBindings.appId GROUP BY apps.id';
+const PB_QUERY = 'SELECT id, GROUP_CONCAT(CAST(appPortBindings.hostPort AS CHAR(6))) AS hostPorts, GROUP_CONCAT(appPortBindings.environmentVariable) AS environmentVariables, GROUP_CONCAT(appPortBindings.type) AS portTypes, GROUP_CONCAT(CAST(appPortBindings.count AS CHAR(6))) AS portCounts FROM apps LEFT JOIN appPortBindings ON apps.id = appPortBindings.appId GROUP BY apps.id';
 const ENV_QUERY = 'SELECT id, JSON_ARRAYAGG(appEnvVars.name) AS envNames, JSON_ARRAYAGG(appEnvVars.value) AS envValues FROM apps LEFT JOIN appEnvVars ON apps.id = appEnvVars.appId GROUP BY apps.id';
 const SUBDOMAIN_QUERY = 'SELECT id, JSON_ARRAYAGG(locations.subdomain) AS subdomains, JSON_ARRAYAGG(locations.domain) AS domains, JSON_ARRAYAGG(locations.type) AS subdomainTypes, JSON_ARRAYAGG(locations.environmentVariable) AS subdomainEnvironmentVariables, JSON_ARRAYAGG(locations.certificateJson) AS subdomainCertificateJsons FROM apps LEFT JOIN locations ON apps.id = locations.appId GROUP BY apps.id';
 const MOUNTS_QUERY = 'SELECT id, JSON_ARRAYAGG(appMounts.volumeId) AS volumeIds, JSON_ARRAYAGG(appMounts.readOnly) AS volumeReadOnlys FROM apps LEFT JOIN appMounts ON apps.id = appMounts.appId GROUP BY apps.id';
-const APPS_QUERY = `SELECT ${APPS_FIELDS_PREFIXED}, hostPorts, environmentVariables, portTypes, envNames, envValues, subdomains, domains, subdomainTypes, subdomainEnvironmentVariables, subdomainCertificateJsons, volumeIds, volumeReadOnlys FROM apps`
+const APPS_QUERY = `SELECT ${APPS_FIELDS_PREFIXED}, hostPorts, environmentVariables, portTypes, portCounts, envNames, envValues, subdomains, domains, subdomainTypes, subdomainEnvironmentVariables, subdomainCertificateJsons, volumeIds, volumeReadOnlys FROM apps`
     + ` LEFT JOIN (${PB_QUERY}) AS q1 on q1.id = apps.id`
     + ` LEFT JOIN (${ENV_QUERY}) AS q2 on q2.id = apps.id`
     + ` LEFT JOIN (${SUBDOMAIN_QUERY}) AS q3 on q3.id = apps.id`
@@ -2025,8 +2017,6 @@ async function updateApp(app, data, auditSource) {
     error = await checkManifest(manifest);
     if (error) throw error;
 
-    // TODO check if checklist needs to be adjusted either here or in the apptask
-
     const updateConfig = { skipBackup, manifest, appStoreId }; // this will clear appStoreId when updating from a repo and set it if passed in for update route
 
     // prevent user from installing a app with different manifest id over an existing app
diff --git a/src/apptask.js b/src/apptask.js
index 740b3fb1d..d587e8b95 100644
--- a/src/apptask.js
+++ b/src/apptask.js
@@ -633,23 +633,42 @@ async function update(app, args, progressCallback) {
     await services.teardownAddons(app, unusedAddons);
     if (Object.keys(unusedAddons).includes('localstorage')) await updateApp(app, { storageVolumeId: null, storageVolumePrefix: null }); // lose reference
 
-    // free unused ports
-    const currentPorts = app.portBindings || {};
+    // free unused ports. this is done after backup, so the app object is not in some inconsistent state should backup fail
     const newTcpPorts = updateConfig.manifest.tcpPorts || {};
     const newUdpPorts = updateConfig.manifest.udpPorts || {};
+    const portBindings = { ...app.portBindings };
 
-    for (const portName of Object.keys(currentPorts)) {
+    for (const portName of Object.keys(portBindings)) {
         if (newTcpPorts[portName] || newUdpPorts[portName]) continue; // port still in use
-
-        const [error] = await safe(apps.delPortBinding(currentPorts[portName], apps.PORT_TYPE_TCP));
-        if (error && error.reason === BoxError.NOT_FOUND) debug('update: portbinding does not exist in database: %o', error);
-        else if (error) throw error;
-
-        // also delete from app object for further processing (the db is updated in the next step)
-        delete app.portBindings[portName];
+        delete portBindings[portName];
     }
 
-    await updateApp(app, _.pick(updateConfig, 'manifest', 'appStoreId', 'memoryLimit')); // switch over to the new config
+    // clear aliasDomains if needed based multiDomain change
+    const aliasDomains = app.manifest.multiDomain && !updateConfig.manifest.multiDomain ? [] : app.aliasDomains;
+
+    // clear unused secondaryDomains
+    const secondaryDomains = [ ...app.secondaryDomains ];
+    const newHttpPorts = updateConfig.manifest.httpPorts || {};
+    for (let i = secondaryDomains.length-1; i >= 0; i--) {
+        const { environmentVariable } = secondaryDomains[i];
+        if (environmentVariable in newHttpPorts) continue; // domain still in use
+        secondaryDomains.splice(i, 1); // remove domain
+    }
+
+    const values = {
+        manifest: updateConfig.manifest,
+        appStoreId: updateConfig.appStoreId,
+        memoryLimit: updateConfig.memoryLimit,
+        portBindings,
+        // all domains have to be updated together
+        subdomain: app.subdomain,
+        domain: app.domain,
+        aliasDomains,
+        secondaryDomains,
+        redirectDomains: app.redirectDomains
+    };
+
+    await updateApp(app, values); // switch over to the new config
 
     await progressCallback({ percent: 45, message: 'Downloading icon' });
     await downloadIcon(app);