ViewWillAppear not called for wdiget when dissmiss main app with home button

I go to main app from widget then update the shared data from main application and dissmiss it by tapping on home button. But widget UI is not updating for updated data.

I reload widget data in TodayViewControllers ViewWillAppear but in this case ViewWillAppear is not getting called.

Where can I ask widget to reload the data?

I tried adding notification for Userdefaults data change but it gets called only when I update the data from widget.