A 19-year-old newsletter is providing the latest twist in the convoluted legal arguments involving the SCO Group's claims over Linux.

Published by original Unix licence owner AT&T, the newsletter tells licensees that AT&T would not own code they added to Unix.

Dating back to August 1985 and sent to Unix System V (SVRx) licensees worldwide, the newsletter - called $echo - refers to "several significant changes to the software agreements" made earlier that year.

The newsletter is interesting because SCO's case against IBM is based on SCO's assumption that it owns all the code within IBM's AIX Unix flavour, which is based on Unix System V.

An entry for section 2.01 of the agreement states: "The last sentence was added to assure licensees that AT&T will claim no ownership in the software that they developed - only the portion of the software developed by AT&T."

A copy of the newsletter was sent to SCO earlier this month by Novell's senior vice president and general counsel, Joseph LaSala.

In an accompanying covering letter LaSala said: "SCO's interpretation of section 2.01 is plainly contrary to the position taken by AT&T, as author of and party to the SVRx licences.

"The purpose of $echo is to reach all Unix System V licensees through one defined medium. It serves as a consistent channel of communication to our licensees and keeps them abreast of any product announcements, policy changes, company business and pricing structures."

But SCO has been quick to try and play down the newsletter's significance.

Blake Stowell, SCO's director of public relations, told vnunet.com: "An article by itself in a newsletter does not in one fell swoop change the legal terms of the licences that are held between a company and its licensees.

"Even after that article appeared, IBM and AT&T made no effort to change the terms of the licence between the two companies."

The letter and newsletters can be viewed here.