Microsoft’s update of its Windows 8 operating system, code-named Windows Blue, will be available later this year, supporting a variety of form factors and display sizes, and providing more options for both businesses and consumers.

“The Windows Blue update is also an opportunity for us to respond to the customer feedback that we’ve been closely listening to since the launch of Windows 8 and Windows RT,” said Tami Reller, chief marketing officer and chief financial officer of Microsoft’s Windows business in a post on Tuesday on the progress of Windows 8.

Microsoft shipped Windows RT for ARM-based devices and Windows 8 for devices based on Intel processors in October last year. The update to Windows 8 comes in the wake of sometimes adverse user feedback about the operating system, which is said to have failed to boost flagging PC sales.

Microsoft’s Surface Pro tablet.

First quarter PC shipments, for example, totaled 76.3 million units, down 13.9 percent compared to the same quarter last year, in part because Windows 8 failed to boost sales, and also because of the popularity of alternative computing devices like tablets, research firm IDC said in April.

Reller did not provide details on the features of the upcoming version of Windows 8.

Microsoft has recently crossed the 100 million licenses sold mark for Windows 8, about six months after its general availability, which includes Windows licenses that ship on a new tablet or PC, as well as upgrades to Windows 8. “This is up from the 60 million license number we provided in January,” Reller said.

The company has also seen the number of certified devices for Windows 8 and Windows RT grow to 2,400, and is seeing more and more touch devices in the mix, she added.

“While we realize that change takes time, we feel good about the progress since launch, including what we’ve been able to accomplish with the ecosystem and customer reaction to the new PCs and tablets that are available now or will soon come to market,” Reller said.

The decline in the PC market in the first quarter was worse than the 7.7 percent drop previously forecast, and the market could be headed into further contraction, IDC said in April. Reller, however, continues to be optimistic about the PC business.

Tami Reller.

“The PC is very much alive and increasingly mobile,” she said. The PC part of the market is evolving fast to include “new convertible devices and amazing new touch laptops, and all-in-ones,” she added. Some of these PCs are coming into the market now, and they are more affordable than ever, Reller said. The Microsoft executive said Windows 8 was also built to address a broader market consisting of devices like tablets.

Microsoft has also seen the number of apps in its Windows Store grow six-fold since launch. Over 250 million apps were downloaded from the store in the first six months, with almost 90 percent of its app catalog downloaded every month.

The company claims to be doing well in some of its other services too. It announced Monday that over 250 million people are now using its SkyDrive online file hosting service. Microsoft now has 400 million active accounts for its Outlook.com webmail, after completing the transition of Hotmail users to the new service. The company plans to add more features to Outlook.com, which started with the integration of Skype which is being phased in throughout the world. It now has over 700 million active Microsoft accounts using its services, Reller said.