Apple previously said it would offer the cheaper battery replacements for older iPhones in late January, but it has removed that timeframe from its letter to customers and has confirmed immediate availability in a statement to TechCrunch.

We expected to need more time to be ready, but we are happy to offer our customers the lower pricing right away. Initial supplies of some replacement batteries may be limited.

Apple normally charges $79 for out-of-warranty iPhone battery replacements, but it reduced the price by $50 following a wave of controversy over its process of throttling performance of some older iPhone models with degraded batteries to prevent unexpected shutdowns. The discount will remain in place until December 2018.

In the note, titled “A Message to Our Customers”, Apple apologized for the situation and also said that a future iOS update will give users a better idea of how battery life is affecting the performance of their iPhone.

Apple’s new battery replacement program was announced on Thursday. In early 2018, the company will also issue an iOS software update with “new features”, to let users see if the condition of their phone’s battery is affecting performance.

If you plan on getting the battery of your older iPhone replaced, you should ideally wait for a few weeks as there is likely going to be heavy rush initially.