The company claims that the Linux source code contains proprietary SCO Unix code. In March SCO launched a £620m lawsuit against IBM, accusing the multinational of contributing the disputed code to the Linux open source operating system.
In July SCO announced that corporate users of Linux containing the disputed Unix code would have to pay it a licence fee of $699 (£430) per processor by 15 October, when the charge would double. Now users have until 31 October before the price rise.
SCO also appeared to ease off pressure on UK users of Linux who have not paid its licence fee. In August it said it would invoice Linux users who did not take up its licence option, but this threat has been put on hold.
SCO officials said they were happy with the take up of licences but would not disclose how many had been issued. Details will be available when SCO announces fourth quarter earnings in December, a spokesman said.
Tony Lock, senior analyst at Bloor Research, said users who have purchased open source software should talk to their supplier, rather than SCO.