The Unified Patent Court (UPC) has announced that its CMS API opt-out process has been revised to provide external users with the fastest possible response time, providing new guidelines and specifications for external developers, including guidance on the changes and modifications needed to current developments. The revised process will be in place when the UPC’s sunrise period starts on 1 March and during which European patents may be opted out of the UPC’s jurisdiction before 1 June when the UPC Agreement enters into force and the Court opens. As reported, from 13 February users may test the CMS sunrise functionalities in the CMS test environment. Now the revised API opt-out process will be active from 13 February so users will be able to test the process and update their system. Whereas the CMS sunrise test period was due to end on 24 February, it has now been extended to last until the end of March so from 1 to 31 March users can still test the new API opt-out process in a test environment, in parallel with the sunrise period.