OnePlus grabbed headlines when it launched its first smartphone in 2014 for a couple of reasons. Firstly, the OnePlus One delivered flagship specs for significantly less cash than the devices it was pitched against. Secondly, the Chinese company made the "flagship killer" smartphone desirable by introducing an invite system that consequently made the OnePlus One harder to get hold of than other smartphones.

Since the original OnePlus One, we have seen two more smartphones from OnePlus - the OnePlus 2 and the OnePlus X. Both follow the same lead as the OnePlus One by offering decent specs for a decent price, with the OnePlus 2 aiming at the flagships while the OnePlus X chases the mid-range.

The OnePlus 2 has been kicking around for a while now, launching in July 2015, while the OnePlus X graced us with its presence in October 2015. This feature is all about the next OnePlus device though - the OnePlus 3. As usual, we will update this feature as more speculation and rumours appear, but for now, this is everything we have heard so far about the OnePlus 3, mixed in with some extra speculation for good measure.

Unlike some other manufacturers, such as Apple and Samsung, OnePlus doesn't have a predictable release cycle. The OnePlus One launched at the end of April 2014, while the OnePlus 2 was announced at the end of July 2015 so there isn't an immediately obvious pattern.

One of the co-founders of OnePlus, Carl Pei, said we can expect the OnePlus 3 by "the end next quarter", suggesting around June. Previous claims suggested the OnePlus 3 will be announced in late May and arrive a few weeks later but this won't be the case. OnePlus announced VR headset called Loop which will ship to the 30,000 people quick enough to sign up for one from 6 June. 

The Loop was free, except for shipping costs, and OnePlus said one of the reasons for the promotion was that it will be hosting the OnePlus 3 launch in VR, as well as providing the option to pre-order the new device from within the virtual world. There were two delivery options at the Loop checkout, 1-3 days or 3-7 days, suggesting the earliest date the OnePlus 3 launch will take place is 13 June.

A tweet from @krispitech revealed some images of various packaging options, claimed to be for the OnePlus 3. The options all have a red and white minimalist theme but no release information came with them sadly so we are still waiting for a confirmed date.

The OnePlus One and the OnePlus 2 were almost identical in measurements, which suggested OnePlus found a form factor it thought worked well.

Sandstone Black was a finish that appeared on both the OnePlus One and the OnePlus 2 but a "new design" will be coming for the OnePlus 3 according to co-founder Carl Pei. He said "the company's first phone was a more captivating device than its second generation," adding "he hopes the OnePlus 3 will have 'at least' that special feeling cast by the OnePlus One when users first saw it."

metal body and fingerprint sensor have both been touted, both of which are supported by various image leaks. A couple of these leaks have come from Chinese social network Weibo, the first set of which presented what looked like a HTC device covered with a pretty ugly case that made it hard to see exact details. Since those images, another set appeared on Weibo from a user called @KJuma.

These images not only support the HTC-like design but they show off the handset from a range of angles. If legitimate, they confirm an oval-shaped fingerprint sensor on the front of the device, along with a protruding square rear camera and USB Type-C. Speaker grilles and the headphone jack appear either side of the USB Type-C port, while the power button appears to be a slider on the right-hand side of the handset.

A recent tweet from serial leaker Evan Blass with a press render has also confirmed the features seen in the images from @KJuma. If the image shared by Blass is accurate, the OnePlus 3 looks like it will be a beautiful handset following in the path of previous HTC handsets. A square protruding camera is on board, along with an oval-shaped fingerprint sensor on the front and USB Type-C.  

Both the OnePlus One and the OnePlus 2 offer 5.5-inch displays, both of which have a 1920 x 1080 resolution for a pixel density of 441ppi. We'd expect a similar size for the OnePlus 3, although it has been claimed the OnePlus 3 could come in three different screen sizes comprising a 5-inch model, 5.2-inch model and a 5.5-inch model after all three have leaked in benchmarks. If this is true, it means the OnePlus 3 will cross into OnePlus X territory, which seems like an unlikely move.

Whether OnePlus will up the resolution to Quad HD in order to compete with the likes of Samsung and LG is anyone's guess but we would be inclined to say no for the simple fact of sustaining the low price OnePlus devices are known for.

The leaked specs suggest we will see a Full HD resolution again, which doesn't come as a huge surprise. You never know though, OnePlus could play the numbers game with the OnePlus 3 and up the resolution but we'd expect this will also up the price. 

The previous OnePlus flagships have featured an IPS LCD display but according to Evan Blass, the OnePlus 3 will sport an AMOLED display. Blass doesn't provide any details on size or resolution but AMOLED tends to offer richer and punchier colours than LCD.

The OnePlus 2 offers a 13-megapixel rear camera with a 0.2-second autofocus and optical image stabilisation. The front-facing snapper is 5-megapixels. It didn't operate as well as the likes of the Samsung Galaxy S6 when we reviewed it but the OnePlus 2's camera does a sterling job when it comes to image quality, meaning OnePlus is already on the right path with its cameras.

A leaked benchmark suggests the OnePlus 3 will come with a 15-megapixel rear camera capable of 4K video recording and a 7-megapixel front camera, capable of Full HD video recording. The rear camera is also thought to have autofocus, face detection, HDR and touch focus. We'd take this with a pinch of salt for now though.

We wouldn't be surprised to see OnePlus up the megapixels on the front camera for the OnePlus 3 as the OnePlus X has a higher resolution than the OnePlus 2 and a few changes to the rear would make sense too, although we don't think it will be anything too drastic. The OnePlus 2 performed well so OnePlus might not deem it necessary to change too much for the OnePlus 3.

Hardware is one area that is easier to predict than others if OnePlus follows the same pattern as the OnePlus One and OnePlus 2. Both these devices came with the latest Qualcomm chipset at their time of release, which was the Snapdragon 801 for the OnePlus One and the Snapdragon 810 for the OnePlus 2.

Leaked specs suggest the OnePlus 3 will come with the Qualcomm Snapdragon 820 processor, which makes perfect sense. It has been claimed by iFeng that the OnePlus 3 will come in three models comprising a 32GB variant with 3GB of RAM, a 64GB variant with 6GB or RAM and a 128GB model with 4GB of RAM. This seems a little odd though. GizmoChina claims 32GB with 4GB of RAM and a 64GB option with 6GB of RAM, which seems more likely. The OnePlus 2 comes in 32GB and 64GB storage options.

We'd expect at least 4GB of RAM for the OnePlus 3 given the OnePlus 2 offered this as an option.

Neither the OnePlus One or the OnePlus 2 offered microSD support for storage expansion, but the latest OnePlus X does so it might be that this extends to the OnePlus 3, especially with the talks of a "new design".

OnePlus patented something called Dash Charge and although the US Patent and Trademark Office filing doesn't mention anything specific, reports are assuming the name means a technology similar to Qualcomm's Quick Charge 3.0.

Qualcomm's standard can re-charge devices up to four times faster than conventional charging. Last year's OnePlus 2 lacked a wireless charging option, as well as a quick-charge mode. The Qualcomm Snapdragon 820 chip that the OnePlus 3 is rumoured to be coming with supports Quick Charge 3.0, but both Samsung and LG opted for their own quick charging technologies instead.

Patents should be taken with a large pinch of salt but the OnePlus trademark filing could suggest OnePlus will also opt for its own technology in Dash Charge instead of Qualcomm's standard. Either way, a fast charging option is looking like a possibility for the OnePlus 3.

In terms of capacity, Evan Blass has reported the OnePlus 3 will have a 3000mAh battery, which would be smaller than its predecessor.

The OnePlus One arrived on the scene with a modified version of Android in the form of Cyanogen Mod, while the OnePlus 2 and the OnePlus X both feature the company's own OxygenOS, which is again, a customised version of Android.

We would highly expect the OnePlus 3 to arrive with the next update to the OxygenOS, with a few more features and based on Android Marshmallow. Ultimately, it will be another Android handset like the others are but with a couple of customisation functions. What these will be for the OnePlus 3 remain to be seen but expect the OnePlus 2's features to cross over.

The OnePlus One cost £230 when it first launched, while the OnePlus 2 starts at £239 and creeps up to £289 for the larger storage capacity.

We would expect the OnePlus 3 to stay within a similar price bracket. We'd be surprised to see it go over the £300 mark but it isn't going to be any less than £230. We'd guess a starting price of around £250 for the OnePlus 3, give or take a few pounds. GizmoChina claims the OnePlus 3 will cost around 2299 Yuan (£245) and 2499 Yuan (£265) in China depending on the storage and RAM configuration.

Another report from GizmoChina said the flagship should cost around $310 (£215) and it also suggests two possible variants with the higher-end model claimed to be around $60 (£40) more expensive. The starting price seems a little low though.

Co-founder Carl Pei said it would be offering a "better buying process" for the OnePlus 3, but he didn't clarify whether this means abandoning the invite-only system that applied to the previous OnePlus devices when they first launched. They are now both available without an invite. As we mentioned previously, the OnePlus 3 will be available to pre-order through the virtual world for those with the OnePlus Loop VR headset, but it isn't clear whether the invite system will remain for those without the headset.

The rumours and speculation for the OnePlus 3 will pick up over the next couple of weeks if the May release is accurate, which will help to draw conclusions as to what will and will not appear.

For now, you can expect the OnePlus 3 to arrive with a new design, although expect the size to be similar to the previous models, along with Qualcomm's SD820 processor, at least 4GB of RAM, USB Type-C and more than likely a fingerprint sensor.

We don't expect to see a QHD display, nor iris recognition but a larger battery capacity and a slight increase in price from the OnePlus 2 wouldn't surprise us. We will keep you posted on any findings.