diff --git a/lib/config/migration.js b/lib/config/migration.js
index de3df564e7e1ee2708b051bd6f2f7cb170049499..6ed9b61d2802ef41d59e69b385453b5dcfe032b0 100644
--- a/lib/config/migration.js
+++ b/lib/config/migration.js
@@ -214,10 +214,7 @@ function migrateConfig(config) {
         isMigrated = true;
         migratedConfig.baseBranches = is.array(val) ? val : [val];
         delete migratedConfig.baseBranch;
-      } else if (key === 'schedule' && !val) {
-        isMigrated = true;
-        migratedConfig.schedule = [];
-      } else if (key === 'schedule') {
+      } else if (key === 'schedule' && val) {
         // massage to array first
         const schedules = is.string(val) ? [val] : val;
         // split 'and'
diff --git a/lib/workers/branch/schedule.js b/lib/workers/branch/schedule.js
index 5f541a14844ad18556ee6903ff4378c0ae7c231f..3b6e63e98f2ba12a5bf1d542227c726063213688 100644
--- a/lib/workers/branch/schedule.js
+++ b/lib/workers/branch/schedule.js
@@ -21,6 +21,9 @@ function hasValidTimezone(timezone) {
 
 function hasValidSchedule(schedule) {
   let message;
+  if (!schedule) {
+    return [true];
+  }
   // check if any of the schedules fail to parse
   const hasFailedSchedules = schedule.some(scheduleText => {
     const massagedText = fixShortHours(scheduleText);
diff --git a/test/config/__snapshots__/migration.spec.js.snap b/test/config/__snapshots__/migration.spec.js.snap
index ae963250b6ff983205402ba8dc91ddaa0293960e..917a9d2b9f91da3b2d19289b36f1464150e0ec02 100644
--- a/test/config/__snapshots__/migration.spec.js.snap
+++ b/test/config/__snapshots__/migration.spec.js.snap
@@ -98,7 +98,7 @@ Object {
       "minor": Object {
         "automerge": true,
       },
-      "schedule": Array [],
+      "schedule": null,
     },
     Object {
       "depTypeList": Array [
diff --git a/test/workers/branch/schedule.spec.js b/test/workers/branch/schedule.spec.js
index 1f55a95435e300a28faa6a85e3ccf28cfe1af538..f5ba42dee3f84a0292251439ed2ce557b696427a 100644
--- a/test/workers/branch/schedule.spec.js
+++ b/test/workers/branch/schedule.spec.js
@@ -14,6 +14,9 @@ describe('workers/branch/schedule', () => {
     beforeEach(() => {
       jest.resetAllMocks();
     });
+    it('returns true for null', () => {
+      expect(schedule.hasValidSchedule(null)[0]).toBe(true);
+    });
     it('returns false for invalid schedule', () => {
       expect(schedule.hasValidSchedule(['foo'])[0]).toBe(false);
     });