Microsoft is expected to announce new versions of its existing Surface computers on Tuesday evening at an event it is hosting in New York.

Microsoft launched the Surface Pro, the latest version of its laptop/tablet hybrid computer, in June 2017. It hasn't updated that computer since. Also, about a year ago, Microsoft launched the Surface Book 2 and the Surface Laptop, two computers that could use an update to Intel's latest eighth-generation processors. Microsoft may also use its event to unveil a new version of its desktop computer, the Surface Studio, which was initially announced two years ago in October 2016.

Microsoft Surface computers are becoming increasingly important. In August, the company said that Surface device revenues were up 25 percent, thanks to some of the devices that it launched earlier in the year.

The timing is also important. Apple is expected to refresh several of its Mac computers this fall, potentially as soon as this month. A report from Bloomberg in August said Apple is planning a new cheaper MacBook Air with a Retina display and a new Mac Mini Pro.

Correction: This story was revised to correct when the Surface Pro was launched. It was in June 2017.