Citrix Monday is unveiling the newest version of its flagship product, which underwent a recent name change as Citrix tries to align its traditional application delivery tools with its new desktop and server virtualization technology.

Citrix, long known for its Presentation Server application delivery software, changed the product line's name to "XenApp" in February and started touting its leadership in application virtualization. The change in focus came a few months after Citrix purchased server virtualization vendor XenSource. Citrix is stressing the complementary nature of XenApp, its XenServer hypervisor and its XenDesktop desktop virtualization product.

Citrix on Monday released XenApp 5, which replaces Presentation Server 4.5, and urged customers to combine the tool with its other Xen products for "an end-to-end virtualization solution that spans servers, applications and desktops."

Citrix says XenApp 5 features load times as much as nine times faster than the previous version, more closely approximating the experience of using a natively installed desktop application. Because applications are hosted remotely and streamed out to users, they don't have to deal with the typical hassles such as upgrading to new versions or restarting when there's a problem, says Bill Hartwick, senior director of product marketing for Citrix's application virtualization group.

"When it's streamed down to me I don't have to worry about installing it or anything. I always have the latest, greatest version of it," he says. "Not only does it start up quickly, but should anything go wrong with the application, I can just re-stream it."

XenApp places applications on centralized servers, allowing users to connect to them from remote devices. To the user, it appears as if the application had been installed on the desktop. Essentially, the presentation layer or user interface is virtualized, says Barb Goldworm, founder and chief analyst for FOCUS Consulting. "Rather than run it on your own desktop, you're running it on a server, virtualizing the presentation layer and distributing it over the network," she says.

Citrix has gone further than any other vendor in terms of virtualizing both desktops and applications, Goldworm says.

Server virtualization giant VMware got into the application virtualization market this year by purchasing Thinstall, which has been renamed ThinApp. Microsoft offers an application virtualization product called App-V.  

Citrix's XenApp 5 has new load balancing functions letting IT administrators ensure that key users and applications receive the best performance available, Hartwick says. The new version uses the HTTP and HTTPS protocols for the first time, features a redesigned interface and integrates XenApp with Citrix's Branch Repeater software, accelerating delivery of applications to branch offices.

XenApp 5 ranges in price from $350 to $600 for each concurrent user.