Google has announced that Android 4.0, also known as Ice Cream Sandwich, will no longer be supported in future releases of Google Play services. As such, devices still running on that version of the OS will no longer receive updates for the Play Services APK after version 14.7.99.
Android 4.0 debuted in 2011, which means it's now seven years old, and its usage share is very low among active Android devices. Since April of last year, it's accounted for less than 1% of Android users and has continuously dropped since then, sitting at just 0.3% in October.
Dropping support for the OS means that future releases of the SDK may not work if you're building apps that still support it. The solution recommended by Google is pretty straightforward - simply target API Level 16 or higher as the minimum required version. API Level 16 refers to Android 4.1 Jelly Bean, which continues to be supported for the time being. Doing so means that end users can still download the latest available release that supports Ice Cream Sandwich, but newer updates that target newer versions of Android won't show up.
If you really want to continue supporting Android 4.0 devices, you can build separate APKs using different versions of Google Play services, or stick with the older SDK components altogether.
Naturally, this news won't affect a whole lot of people, as the majority of apps is likely to have dropped support for Ice Cream Sandwich already. With that being said, if you're still rocking one of these devices, it may be time to upgrade.