Apple today updated its sales policy in Hong Kong to indicate all products purchased at Apple's online and retail stores in the country on and after August 15, 2017 cannot be returned or exchanged indefinitely.

As an exception to the rule, Apple will still honor exchanges for defective products in Hong Kong at its sole discretion.

Apple didn't provide a reason for the policy change, but it's likely a precautionary move ahead of new iPhone models expected in September. The same policy went into effect in Hong Kong on iPhone 7 launch day last year.

Hong Kong is a hotbed for black market electronics due to the lack of import taxes and duties added to foreign goods purchased, as is the case in neighboring mainland China. Scalpers often attempt to illegally smuggle new iPhones across the border to mainland China to make significant profits.

Hong Kong scalper spotted "walking strangely" across the border into mainland China in 2015 via South China Morning Post

When the iPhone 7 and iPhone 7 Plus launched in Hong Kong last year, for example, the smartphones hit the black market for as much as $15,000 in Hong Kong dollars, which was slightly over $1,900 in U.S. dollars.

Apple's standard return policy in Hong Kong is already stricter than in some other countries. For volume purchases of four products or more, the return window is seven days, and there is a 25 percent restocking fee per unit.

Apple will likely revert back to its standard return policy in Hong Kong at some point, but it didn't specify when.