Microsoft has invited press and bloggers to a "small gathering" in New York City on May 20. As the invite suggests, the firm will finally launch its delayed Surface mini. But I'm told we might also see another surprise at the event.

"Join us for a small gathering," the invite notes.

Microsoft originally intended to launch Surface mini last fall alongside Surface 2 and Surface Pro 2. But as a report in Neowin accurately revealed, the firm delayed the release of Surface mini because of production issues that also curtailed availability of Surface 2 throughout late 2013. The device Microsoft will launch this month is unchanged from the one it planned to deliver late last year, my sources tell me.

Like Surface 2, Surface mini will be based on an ARM chipset and will run Windows RT 8.1. But this device further differentiates from the mini tablet competition by providing a very accurate and high quality stylus for note-taking and OneNote integration. It is expected to become publicly available in late June alongside a click-in cover with a multi-position kickstand and a possible second Surface device that could also be revealed at the May 20 event.

According to Mary Jo Foley's sources, Microsoft CEO Satya Nadella will be officiating the launch event.

As you might expect, news about Surface mini started, um, surfacing again a few weeks ago when Foley reported on an aftermarket case for the device. But although my sources tell me now that the case design is bogus and that the company that makes it is not an official partner, they were clearly tipped off to the anticipated Surface mini launch date, which Mary Jo's sources accurately said would happen in May.

Given the Surface mini's focus on note-taking, the device could prove to be a hit among those who have been waiting for such a device. The current crop of stylus-supported Windows mini tablets, including the Dell Venue 8 Pro and Lenovo ThinkPad 8, offer only basic stylus capabilities, and if Microsoft gets this right it could be a real differentiator. That said, the firm's decision to use Windows RT 8.1 instead of "real" Windows could turn off some users too.