Just weeks before the Apple Watch Series 8 lineup is expected to be unveiled, the Apple watch edition has sold out in many countries.

Several of the high-end Apple Watch Series 7 models were being listed as currently unavailable on Apple's online store in the United States, Canada, the United Kingdom, and other countries.

In September, the Apple Watch Series 8 is expected to be unveiled. According to Mark Gurman, Apple plans to introduce a high-end model with a larger display and a more durable design that would be suitable for hiking and extreme sports.

The Apple Watch Edition has only been available for a short time, but it is rumored that the high-end model will have a titanium case. With the Apple Watch Edition being the only differentiating feature, it's hard to see how it could be justified in the lineup with a substantially different titanium model placed just above it.

The new high-end Apple Watch is expected to sell in relatively low volume, just like previous reports of low sales for the Apple Watch Edition models due to their high price point, according to display analyst Ross Young. Four million Apple Watch Series 8 models are expected to be shipped in the third quarter of this year, compared to one million for the larger Apple Watch.

Gurman's confirmation of a titanium case for this year's new high-end Apple Watch model is the best indication yet that Apple may be folding the current Apple Watch Edition line into this new product category. It would be possible to continue to offer a titanium case, but more so tout the weight and strength advantages of the material at a higher price point.

Leaving the more affordable titanium Apple Watch Edition in the lineup could cause a cannibalization of sales of the new high end model. The new high-end Apple Watch could be more appealing to some customers than the Apple Watch Edition, with meaningful differentiating aspects such as display size, battery life, and design providing more justification for an up sale.

With names like Apple Watch "Pro" being far from locked-in at this stage of the rumor cycle, it's worth noting that the new high-end Apple Watch models could just form the Apple Watch Edition line going forward. It appears that the Apple Watch Edition line may not be around anymore. Beyond a redesign, the high-end Apple Watch is expected to feature the "S8" chip, a body temperature sensor for enhanced sleep tracking and fertility planning, a low power mode to prolong battery life, and a larger battery to enable longer workouts.