In terms of pre-launch buzz, the iPhone 7 and 7-plus, due to be unveiled by Apple (AAPL - Get Report)  at a Wednesday event starting at 1 p.m. Eastern Time, certainly doesn't carry the hype that surrounded the iPhone 6 and 6-plus before those phones launched two years ago.

In addition, the fact next year's iPhones are rumored to sport several eye-catching features could make Apple's efforts to get customers to upgrade more difficult. As might the fact American consumers have been waiting longer to upgrade their smartphones as traditional smartphone subsidies disappear.

Still, following the iPhone 6S' soft reception, Apple has to be well-aware it needs to provide a more compelling set of new features to drive strong upgrade activity. And the list of improvements rumored to be provided by the iPhone 7 is a little stronger than conventional wisdom might suggest.

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Here's a look at the most noteworthy new features to be delivered by a 4.7-inch iPhone 7 and 5.5-inch iPhone 7-plus:

A better display (possibly much better) - The display found on the 9.7-inch iPad Pro, which launched earlier this year, has won rave reviews for its color accuracy, anti-reflective coating and -- through a feature known as TrueTone -- ability to adjust the display's color balance based on the ambient lighting a user is dealing with. The iPhone 7 is expected to feature at least some of these enhancements.

This year's iPhones aren't, however, expected to sport OLED displays. That's a feature widely reported to be arriving with next year's models.

Twice as much storage - The cheapest iPhone 7 models are expected to sport 32GB of storage, twice as much as is found in the cheapest 6S models. Likewise, more expensive iPhone tiers are expected to see their storage capacities double to 128GB and 256GB.

A dual-lens camera (7-plus only) - Arguably the rumored feature that has produced the most enthusiasm. Relying on technology obtained through Apple's 2015 purchase of startup LinX, the iPhone 7-plus will reportedly forgo a standard rear camera in favor of a dual-camera array that allows for better low-light shots and superior image quality in general.

The use of dual lenses could also enable some innovative features, such as optical zoom (in the absence of a mechanical zoom lens), automatic background removal, 3-D object modeling and the ability to change a picture's focus point after it has been taken. We'll have to wait for Apple's event to see which of these features the company chose to include.

Better battery life - The 4-inch iPhone SE, which launched in May, delivered about a 20% improvement in battery life relative to the 6S, in spite of having very similar internals. The iPhone 7's battery life will also likely outpace the 6S'.

A faster processor - Apple has included a new processor with each new flagship iPhone, and the iPhone 7 shouldn't be any different. An A10 processor, believed to be made using Taiwan Semiconductor's (TSM - Get Report) 16-nanometer manufacturing process, is expected to succeed the A9 processor found in the 6S.

A pressure-sensitive home button - Though the iPhone 7 is still expected to feature a physical home button -- next year's iPhones might do away with them -- Bloomberg reports the button will respond to pressure "with a vibrating sensation rather than a true physical click." That opens the door for advanced haptic controls similar to what's provided by the Force Touch trackpads found on certain MacBooks. Haptic technology developer Immersion (IMMR - Get Report) , which is suing Apple for patent infringement, might be pleased to see this.

Waterproofing - KGI Securities analyst Ming-Chi Kuo recently reported the iPhone 7 will provide water-resistance on par with that of the Apple Watch, while adding the revamped home button will help make this possible. Samsung has long advertised the water-resistance of some of its high-end phones.

No traditional headphone jack/new headphones - Easily the most controversial rumored change. The iPhone 7 is expected to do away with the traditional 3.5-millimeter headphone jack, and instead require headphones to connect through the phone's Lightning port. To make the transition easier, Apple will reportedly bundle an adapter and a pair of Lightning earbud headphones with the iPhone 7.

There are also rumors Apple is planning to launch a pair of low-power wireless earbuds that will be sold as an optional accessory.

More memory (7-plus only) - The iPhone 7-plus is rumored to feature 3GB of RAM, 1GB more than what the 6S-plus contains. The regular iPhone 7 will reportedly still have only 2GB of RAM.

Stereo speakers (kind of) - Kuo reports Apple plans to allow the iPhone 7's earpiece receiver to function as a speaker when a phone is used in landscape. The receiver will work with the phone's regular speaker to provide stereo sound.

Taken in aggregate, the rumors do point to a much bigger set of improvements than what was delivered by the iPhone 6S, particularly for the iPhone 7-plus. Whether these improvements will drive a healthy iPhone upgrade cycle remains to be seen.

EDITORS' NOTE: This article was originally published on Sept. 6.