I have several clients that want to have a mobile app for their clients. In every case so far, the APP development can be circumvented by showing the client (and his clients) how to use a simple feature accessible to everyone with a smart phone.
Client A: I want to notify my clients when my hours are extended to accommodate changing weather conditions
Client B: I want to let my clients know when we have just created a new special (coupons)
Client C: I want to release critical information about malware and phishing schemes before my clients get caught
Client D: I want a program for critical announcements related to our business and our clients products
Client E: I want a reminder program that sends specific instructions and tasks to my clients at the appropriate times
I can go through the alphabet and think of many more situations like this. In short, the request is almost always the same. The simple answer to EVERY ONE of these is RSS. Your challenge is not to develop a mobile application, but to educate your clients on the use of RSS on their smart phone devices. Each of the above scenarios can be enabled with a blog and associated RSS for that blog. (including this blog).
The apps I like:
Android: RSS Alert and Lite RSS. Both will poll an RSS feed and send a notification for new articles.(both FREE and ad free)
ios: Free RSS reader.
ios is a little more finicky about how RSS works and wants to use the news app by default (which is ok but over the top for simple announcements).
Also, one of my favorite APPs that hands RSS nicely is IFTTT. It works on both ios and android and is extensible to other devices if you get good with the app.
As a test, I have the RSS for this blog hooked up to my phone (Android). Within 5 minutes of submitting this blog I received a notification that a new blog was submitted. (using both RSS Alert and IFTTT - so I got two notifications).