The upgrade is causing a ripple effect on the popular OpenNap shadow network, which now faces technical problems that could incite many of its members switch to alternative services.
Kelly Truelove, chief executive of Clip2.com, a company that tracks and supports peer-to-peer file-swapping services, said Napster's new software makes it harder to use OpenNap servers.
"Napster with its new client has not only blocked access to Napster from its cloned client, it's also made it impossible to utilize the Napster client to connect to the clone server," Truelove said. "This break-in compatibility does have for the moment a profound effect on how easy it is to get connected to those clone servers."
OpenNap allows people to set up their own file-swapping hubs that--like Napster's own servers--create indexes of songs available on other people's hard drives. The Napigator software program acts as a road map to this Napster underground, letting people point their regular Napster software to one of these independent file-trading hubs instead of to the company's servers.
Napigator has already posted a notice on its Web site saying the application does not work with Napster's beta 10.3 software. As a result, new members will be unable to download Napigator.
Analysts said the crackdown could see file swappers migrate to a host of rival services, such as Audiogalaxy, Music City Morpheus, KaZaa, BearShare, LimeWire, iMesh and others. Jarvis Mak, senior Internet analyst at Nielsen/NetRatings, said Napster's usage has already taken a nosedive, and the new software will further reduce the number of downloads and the level of activity on Napster itself.
The popular service has been in a legal struggle with the Recording Industry Association of America, which sued it in December 1999, alleging it violated copyrights.
"People are already making the shift toward other file-sharing programs," Mak said. "What (Napster's) expecting is as people transition from their old software to the new software, that that level will come back up and the number of songs will increase. But I highly doubt it will reach the levels that it (reached) before the RIAA sued them and they were ordered by the courts to modify the service (because) there are alternatives that are not restricted as of yet."
After Napster, OpenNap servers were one of the record industry's earliest targets. In February, record industry representatives contacted Internet service providers in more than a hundred cases, asking them to block access to subscribers' computers that were offering Napster-like file-trading facilities.
Despite its legal and technical woes, Clip2's Truelove said he doesn't expect OpenNap to disappear yet.
"The outside world of clones emerged out of a reverse-engineering effort that has been going on for some time," he said. "We may see some attempt to reverse-engineer this and get around" Napster's new filters.