Napster plans to shut off old versions of its file-swapping software late Wednesday night to push a version that includes a new filter for blocking copyrighted music. Napster is funneling people to a new version of the software that includes technology supposedly able to identify a song accurately using a digital representation of its sound. When it released the software last Friday night, the company touted it as a way to release many previously blocked songs back into its network. Readers, however, report that almost no songs are getting through the network with the new software. A quick look at the Napster network gave access to about 1,600 songs -- fewer than some MP3 lovers have on their own hard drives. According to consulting firm Webnoize, which has tracked Napster usage over the past few months, the average Napster user was sharing just 1.5 files by Wednesday morning, as compared to about 220 files in February. "By further reducing the music available through the current service, Napster has provided another nail in the coffin of the service consumers originally loved," Webnoize analyst Matt Bailey said in a statement. The massive drop in the number of files available isn't intentional. The company ruefully says that bugs in the filtering system are still being worked out and that the software development is being done on a legal time frame instead of on a software development schedule. Napster aims to comply with a court order banning the trade of most copyrighted works over its service. Bugs in the software aside, it's also emerging that the task of cross-referencing the unique audio characteristics of hundreds of millions of songs with a list of off-limit songs is a technical and logistical nightmare. Napster is getting much of the audio "fingerprints" that identify specific songs from digital encoding services provider Loudeye Technologies. This information is then cross-referenced with the list of songs provided by the record companies, creating the information used to block file transfers. But it's not that easy. People name songs many different ways, and compressing songs or otherwise changing the file slightly can change the audio fingerprint, so it's not as simple as turning on a simple check-and-block system. And this time, after repeated admonitions from the court, the company is erring on the side of safety. "They're taking extraordinary caution to make sure that the [songs identified by the record companies] aren't slipping through," a Napster spokesperson said. This means songs that aren't on the record companies' list will have to trickle back into circulation a little at a time as Napster ascertains that they are or aren't on the must-block list. At least at this stage, this is a laborious process, in some cases even involving people hand-checking a song against its audio fingerprint to make sure the file should be allowed into the system. Whether people will stay on the service as the number of songs slowly climbs back up from the ground is an open question. That's a critical measure, as the company is trying to hold on to as many members as possible as it moves toward launching a new subscription service as soon as next month. "With little music available now, users continue to drift away from Napster," said Bailey. Napster lovers have already begun to complain. Last weekend, after downloading the new software, Napster user John Quincy said he found it virtually useless. The old "Napster allowed me to share about 160 of the nearly 700 MP3 files in my shared folders. Napster [version] 10.3 allowed me to share zero files, not more files," even with the program configured correctly, he wrote in an email to News.com. "Needless to say, I got rid of [version] 10.3 and went back to 10.2." Starting Thursday, he and millions of others won't have that option. Despite the Napster crackdown, however, file swapping is alive and well on numerous Napster clones that provide access to a wide range of top hits for free. Although Napster's decision to force the switch may bring it into compliance with the court, it will likely hasten the exodus of former fans to such alternatives, which include Audiogalaxy, Music City, Morpheus, Kazaa, BearShare, LimeWire, iMesh and others. The Internet is changing the face of the music industry forever. Find out more in ZDNet UK's MP3 News Section. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Napster Debate. Let the editors know what you think in the Mailroom. And read other letters.