Apple on Tuesday officially announced its second fiscal quarter earnings, revealing a total revenue of $58 billion. And while it’s logical to assume that millions of iPhones were sold in the latest quarter, it turns out the iPhone trade-in efforts from Apple helped quite a bit.

During the follow-up quarterly earnings call to go over some details, Apple’s CEO, Tim Cook, said that the trade-in initiatives the company launched were very successful. Cook said that the company saw over four times the number of trade-ins when compared to the same quarter last year.

Apple launched the attractive trade-in program back in December of last year. It arrived first in the United States, then expanded internationally soon after. For those who took advantage of the program, it saw trade-ins getting an additional $100 towards a new device in some cases. In other instances, Apple would offer a boost of around $25.

While it’s technically possible to still trade your older iPhone model for a new handset, this particular promotion is not currently available. However, with how successful this promotion was, it seems like a safe bet that we may see it pop up again later this year.

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