Apple announced today that new Mac apps and app updates will no longer be able to use garbage collection, a system for managing an application's memory use, after May 1. Instead, developers must switch to using Automatic Reference Counting (ARC).
Garbage collection was deprecated quite some time ago in OS X Mountain Lion as Apple wanted developers to start adopting ARC, which made its debut in the previous version OS X Lion.
As developers make the transition, Apple notes that they can take advantage of the migration assistant in Xcode to ease the process.
Source: Apple
