Facebook apps using the current Open Graph API will break on April 30, 2015. Facebook emailed iPod and iPad developers today (see below), explaining why their apps will break if they wait until the deadline to upgrade to Graph API v2.0.
Facebook's email to developers:
Upgrade Your Apps to Graph API v2.0+ Now
At our f8 event, we introduced Graph API v2.0. API versions older than v2.0 expire on April 30, 2015. After this date, your apps will automatically be upgraded to v2.0.
Our data shows that it takes 80-140 days for 90% of people to update to the latest version of a mobile app. Because of this, we recommend you ship an updated version of your app using Graph API v2.0+ to the app store by December 25, 2014 at the latest.
If you have any questions, please check out the FAQs.
Learn How to Upgrade
Explanation of Facebook's Email to Developers
Facebook apps in production use what Facebook is calling Graph API v1.0, more commonly known as "Open Graph" or "the Graph API." If you develop on the Facebook platform, you need to look at how Graph API v2.0 will affect your app.
The "Holiday Shutdown" part of the timeline above shows when Apple's App Store shuts down around Christmas ever year. App Store approval processes can be painfully slow for developers with broken apps. Facebook is probably reminding app developers of this upgrade delay, with the holiday shutdown a nice way to put a red warning on the timeline.