Over the past decade, cellular phones have evolved from delivering aggressively buzzy vibrating alerts to more nuanced “haptic feedback” — digitally created forces that respond to touch. While there were evolutionary steps before Apple debuted the iPhone 6S with a Taptic Engine, that 2015 device marked a turning point for smartphone haptics, bringing deeper and more realistic touch sensations into pocketable devices. Now there’s a report that Apple will upgrade the Taptic Engine for the iPhone 11 family, so I’ve assembled some clues regarding the types of new features it might include.

It’s worth noting up front that neither today’s 9to5Mac report nor Apple’s key Taptic Engine supplier, Japan’s Nidec Seimitsu, offers any concrete details on what the next-generation vibration actuator might do. Moreover, Apple has been more conservative in using haptics than Android rivals, even shying away from using mini vibrations to confirm virtual keyboard presses. So treat the following list as a collection of possibilities rather than anything definitive and you won’t be disappointed when the new iPhones are unveiled in September.

1. More complex vibrations. Nintendo’s Switch debuted a distinctive haptic feature called HD Rumble, which has famously simulated sensations such as multiple ice cubes clinking in a glass or dice rattling in a box. Immersion, the company behind that feature, suggested nearly a decade ago that its HD haptics would become popular in smartphones. Since then, it’s continued to advance similar features in Android devices.

In Apple’s hands, complex next-generation haptics could empower a wider and more nuanced range of responses to input: the feeling of a finger navigating over bumps, a pencil dragging against paper, or thumps that appear to be coming from different locations inside the iPhone. That said, there have been signs for years that Apple has wanted to add complex haptics like these to bigger-screened iPads, but it just hasn’t happened, supposedly due to the engineering challenges of distributing sensations across larger surface areas — but possibly due to patent concerns.

An otherwise slow (read: no 5G) iPhone year like this could be a good time to overhaul the device’s entire interface with haptic feedback. It might be too much to hope for Apple to implement Android-style key tap haptics for the virtual keyboard at this point, but perhaps the company was waiting on a very specific type of key feedback that only a next-generation actuator could deliver. Or maybe it’s once again hoping that third-party developers will come up with more novel uses of the idea.

2. More frequent vibrations across different types of apps. If a vibration motor consumes relatively little power and is reliable enough, it could be used for all sorts of purposes without fear of either killing the device’s battery or breaking. Nidec describes some of its motors as capable of “interlocking” with music and games to vibrate along with beats, creating the sense of “listening to a music performance in a concert hall,” or immersion in the action.

Apple has historically underplayed the vibration capabilities of its devices, using the little motors largely to respond to inputs rather than as persistent output drivers — except for silencing ringtones. But with the right component, and the right support from Apple’s software teams, anything’s possible.

3. More powerful vibrations. This one is possible, but hard to imagine in an Apple device: The next Taptic Engine might be capable of really rattling your hands when necessary, coming closer to the jostle of a game controller than the buzz of a smartphone. For a variety of physical reasons, including ever-thinning iPhone chassis designs and the potential for abuse, this one seems somewhat unlikely.

4. Less powerful or disruptive vibrations. As boring as this sounds, it’s not as implausible as it might seem. Prior to the Taptic Engine, Apple changed the vibration actuators in earlier iPhones to reduce their likelihood of accidentally vibrating (largely glass, easily breakable) devices off of flat surfaces. Given Apple’s continued focus on luxury experiences, it might want to preserve the current Engine’s vibration sensations without making them feel as harsh. It might also want to cut the power consumed by the actuator to improve device battery life.

My guess is that this one is largely unlikely. The Taptic Engine is already capable of delivering relatively low-power taps that are almost impossible to feel unless the phone is in your hand, and users tend to complain when they can’t feel the device’s promised haptic responses. Apple wouldn’t need an all-new part to deliver weak haptics, either. But it’s possible that a next generation Taptic Engine could be more power efficient or support a wider range of force levels.

5. Mid-air vibrations, at a distance. As wild as this sounds, a company called Ultrahaptics has created an ultrasonic haptics system that can be felt in the air, without physically touching the actuator — a system that notably has potential applications in the AR and VR spaces. The idea is to let people physically feel and manipulate virtual objects they’re seeing through AR or VR headsets, providing up to eight separate touch points at up to 27.5 inches away from the device.

You might recognize Ultrahaptics’ name from its May acquisition of Leap Motion, a company Apple reportedly considered buying and ultimately walked away from. Moreover, since 9to5Mac’s report today claims that the new Taptic Engine is “known by the codename leap haptics,” that could be a clue.

I won’t be holding my breath on this one, though, due to Ultrahaptics’ system’s size and the lack of obvious value in implementing such a feature — yet — in an iPhone. The company’s publicly known actuators are closer to laptop-sized than pocketable, and there’s no indication that the company has developed something that could fit inside a smartphone. Even if it did, the value would be questionable: Without an AR/VR-style image floating in front of your phone, what need would you have for mid-air haptics?

For years, there have been suggestions that Apple and others were working on mid-air gesture controls for various devices, and sure, it might be cool to “feel” the press of a floating play/pause button or a sliding volume control that isn’t actually there. But without AR or VR glasses, you’d need to view UI elements and other objects through the iPhone’s own screen, which you’d be holding in your hand with no need for mid-air haptics. This doesn’t really add up.

Realistically, if the iPhone 11 does in fact get a new Taptic Engine, the most likely innovations would be bits and pieces of the first four concepts above — a little extra thump here, a more precise or subtle clink there, and a reliable enough part to keep functioning despite lots of additional triggers from the OS and apps. In a year when I’m leaning towards holding off on purchasing a new iPhone, my personal hope is that Apple has decided to deprecate 3D Touch for a good reason, and has ambitious haptic plans in store for September.