This should be able to be setup using a view setting of "Until Click-Through" and the trigger being set to "Launched" with a value of "exists". With these settings, the message would be displayed every time the app is launched as long as the following is true:
- the message has not been previously clicked through.
- the current lifecycle session is expired. The default lifecycle session time is 300 seconds. If the app had been closed or in the background for 300 seconds or more then relaunched, a "Launched" event will be triggered thus triggering the in-app banner message.
Please let me know if you have any additional questions.