diff --git a/migrations/20190426172858-migrate-caas-backupConfig.js b/migrations/20190426172858-migrate-caas-backupConfig.js
new file mode 100644
index 000000000..0e3670117
--- /dev/null
+++ b/migrations/20190426172858-migrate-caas-backupConfig.js
@@ -0,0 +1,19 @@
+'use strict';
+
+exports.up = function(db, callback) {
+    db.all('SELECT value FROM settings WHERE name="backup_config"', function (error, results) {
+        if (error || results.length === 0) return callback(error);
+
+        var backupConfig = JSON.parse(results[0].value);
+        if (backupConfig.provider !== 'caas') return callback();
+
+        backupConfig.boxId = backupConfig.prefix; // hack to set the boxId that happens to match the prefix
+        delete backupConfig.fqdn;
+
+        db.runSql('UPDATE settings SET value=? WHERE name="backup_config"', [ JSON.stringify(backupConfig) ], callback);
+    });
+};
+
+exports.down = function(db, callback) {
+  callback();
+};
diff --git a/src/caas.js b/src/caas.js
index b4aa87f6b..3dc1f8224 100644
--- a/src/caas.js
+++ b/src/caas.js
@@ -105,7 +105,7 @@ function backupDone(apiConfig, backupId, appBackupIds, callback) {
 
     debug('[%s] backupDone: %s apps %j', backupId, backupId, appBackupIds);
 
-    var url = config.apiServerOrigin() + '/api/v1/caas/boxes/' + apiConfig.fqdn + '/backupDone';
+    var url = config.apiServerOrigin() + '/api/v1/caas/boxes/' + apiConfig.boxId + '/backupDone';
     var data = {
         boxVersion: config.version(),
         backupId: backupId,
diff --git a/src/routes/test/sysadmin-test.js b/src/routes/test/sysadmin-test.js
index b9a885bff..6aa7805b2 100644
--- a/src/routes/test/sysadmin-test.js
+++ b/src/routes/test/sysadmin-test.js
@@ -52,7 +52,7 @@ function setup(done) {
         },
 
         function createSettings(callback) {
-            settingsdb.set(settings.BACKUP_CONFIG_KEY, JSON.stringify({ provider: 'caas', token: 'BACKUP_TOKEN', fqdn: DOMAIN_0.domain, key: 'key', prefix: 'boxid', format: 'tgz'}), callback);
+            settingsdb.set(settings.BACKUP_CONFIG_KEY, JSON.stringify({ provider: 'caas', token: 'BACKUP_TOKEN', boxId: 'boxid', key: 'key', prefix: 'boxid', format: 'tgz'}), callback);
         }
     ], done);
 }
diff --git a/src/storage/s3.js b/src/storage/s3.js
index 923749938..3d6932ab9 100644
--- a/src/storage/s3.js
+++ b/src/storage/s3.js
@@ -62,7 +62,7 @@ function getCaasConfig(apiConfig, callback) {
 
     debug('getCaasCredentials: getting new credentials');
 
-    var url = config.apiServerOrigin() + '/api/v1/caas/boxes/' + apiConfig.fqdn + '/awscredentials';
+    var url = config.apiServerOrigin() + '/api/v1/caas/boxes/' + apiConfig.boxId + '/awscredentials';
     superagent.post(url).query({ token: apiConfig.token }).timeout(30 * 1000).end(function (error, result) {
         if (error && !error.response) return callback(error);
         if (result.statusCode !== 201) return callback(new Error(result.text));
diff --git a/src/test/settings-test.js b/src/test/settings-test.js
index 82171719e..b5a6d49bb 100644
--- a/src/test/settings-test.js
+++ b/src/test/settings-test.js
@@ -100,10 +100,10 @@ describe('Settings', function () {
 
         it('can set backup config', function (done) {
             nock(config.apiServerOrigin())
-                .post(`/api/v1/caas/boxes/${DOMAIN_0}/awscredentials?token=TOKEN`)
+                .post(`/api/v1/caas/boxes/boxid/awscredentials?token=TOKEN`)
                 .reply(201, { credentials: { AccessKeyId: 'accessKeyId', SecretAccessKey: 'secretAccessKey', SessionToken: 'sessionToken' } });
 
-            settings.setBackupConfig({ provider: 'caas', fqdn: DOMAIN_0, token: 'TOKEN', format: 'tgz', prefix: 'boxid', bucket: 'bucket' }, function (error) {
+            settings.setBackupConfig({ provider: 'caas', boxId: 'boxid', token: 'TOKEN', format: 'tgz', prefix: 'boxid', bucket: 'bucket' }, function (error) {
                 expect(error).to.be(null);
                 done();
             });