Apple Inc. NASDAQ:AAPL’s iPhone 6 and 6 Plus smashed all the smartphone sales records in history when they went for sale in September. The company sold over 10 million new iPhone 6 and 6 Plus units in the opening weekend. However, staggering sales were overshadowed by some users reporting that their 5.5-inch iPhone 6 Plus would bend out of shape in their pockets.

iPhone 6 Bendgate: Did Apple Inc. Quietly Fix The Issue?

The iPhone 6 Plus has become sturdier

Bending is not a design flaw in the iPhone 6 Plus. Tests conducted by Consumer Reports have revealed that any device with metal chassis will bend when put under certain amount of force. Samsung Electronics’ brand new Galaxy Note 4 bends, too. Though the bending issue affected only a small number of users, it might have prompted Apple to make its device even sturdier in just a couple of weeks.

According to one Reddit user, the new iPhone 6 Plus he just bought had significant design differences compared to the one he purchased for his wife in the first week of launch. The older model had a smoother and softer aluminum finish, which indicates that the Cupertino company might have toughened the iPhone 6 Plus.

Tapping on the sides and back of the two units produced different sounds from the two iPhone 6 Plus units. The Reddit user said there was “a night and day difference in sound.” He said the new iPhone 6 Plus that he purchased yesterday had a very dull tone, suggesting it was more sturdy than his wife’s phone purchased in September.

New iPhone 6 Plus 21g heavier than the old unit

In fact, he even tried to look through the cracks of the volume buttons using a microscope. He could see a red-color object in the opening of the volume down button in the new model. The older model had no such thing. Notably, that section of the device was a weak spot as, in most cases, the bending would occur near the volume buttons.

Finally, when he weighted the two units, he found that his 128GB iPhone 6 Plus was 21 grams heavier than his wife’s 16GB phablet. Of course, some of that weight could be due to the heavier storage chip. But the storage chip is unlikely to be 21 grams heavier. It’s quite surprising that Apple was able to make these structural changes in such as short time.

Apple Inc. NASDAQ:AAPL shares rose 0.57% to $107.59 at 10:47 AM EDT on Friday.