Xiaomi is sourcing 18.5:9 aspect ratio screens from a supplier called Tianma, but according to industry partner and investor Pan Jiutang, those screens will not be going into Xiaomi Mi MIX 2 units, and will instead wind up in future Redmi products. Jiutang also mentioned that other product lines could be on the list, which could mean that flagship Mi phones could have ultra-wide screens in the near future. According to Jiutang, all Xiaomi Mi MIX 2 units will use JDI screens, leaving the screens from Tianma free for other products. It is worth noting that Tianma is a fairly small operation, which means that the company will likely not be the jumping off point for a full-on transition to 18.5:9 screens across Xiaomi's entire portfolio.
This rumor comes to light just as the upcoming Xiaomi Redmi Note 5 and its Plus variant are making their way into headlines, but photos of those phones themselves apparently have yet to surface. This, of course, adds credence to the rumor at hand. It is worth noting that the Redmi Note 5A does not have an 18.5:9 aspect ratio, but instead adheres to the look and feel of previous generations of Redmi Note devices. The same can be said of the Redmi 5, if the photos currently floating around the web are to be believed.
The adoption of longer screen aspect ratios and smaller bezels started quite a while back, arguably with Sharp's AQUOS Crystal lineup, and the trend quickly picked up steam and went mainstream when Samsung and LG got on board with their Galaxy S8 and G6 flagship phones. From there, the trend has been picked up and both played straight and riffed on by everybody from big-name startup Essential, founded by Android godfather Andy Rubin, to small Chinese OEMs like UMIDIGI. Xiaomi's first phone to adhere to the new ratio was the Mi Mix, though it played the trend a bit differently than how it's seen on the Galaxy S8 and the phones that followed its lead. The Mi MIX 2 followed in its predecessor's footsteps, having almost no bezel to speak of anywhere except the bottom, where the phone has a relatively thick "chin". Since rumors pointed to Tianma making panels for the Mi MIX 2, it is likely safe to assume that the Redmi Note 5 and Redmi Note 5 Plus will follow the same design convention, should they opt for the longer aspect ratio.