Apple is supposedly testing a new version of the iMac, and it has a Retina display.
According to 9to5Mac, which has a good track record with Apple rumours, both unnamed sources and references in OS X Yosemite betas have indicated Apple is currently developing (or rather in the late-testing stage of developing) a new line of iMacs with ultra high-resolution Retina displays. You can expect the new line to launch this autumn, alongside OS X Yosemite, the report claimed.
It's worth noting Apple has yet to give its desktop machine a Retina display. The Cupertino-based company introduced the Retina display with iPhone 4 in 2010 and then added it to MacBook Pros in 2012. There's no word yet on what type of resolution the Retina iMac will boast, but references in betas for OS X Yosemite point to one of the following: 6400x3600, 5760×3240, and 4096×2304.
Apart from the Retina display upgrade, Apple has reportedly kept the iMac's thin profile but included new internal hardware such as faster processors and improved Wi-Fi antennas. The company is allegedly also working on updates to iMovie and Final Cut Pro. They might receive improved tools for editing 4K high-resolution footage - which would of course look great when played back on a Retina iMac.
Apple unveiled its upcoming new Mac operating system, called OS X 10.10 Yosemite, during WWDC 2014 in June. Since then, Apple has opened the beta of OS X Yosemite to developers and some members of the public for testing. Apple has yet to be more specific than an autumn launch, but the latest reports have suggested a 21 October event.
Apple might also unveil new iPads - like the iPad Air 2 and iPad Mini 3- in addition to launching OS X Yosemite and Retina iMacs at its rumoured event.