California plans to exclude Linux and most other open-source operating systems from its new age verification law, which takes effect on Jan. 1, 2027. The change follows massive pushback from the open-source software community.
In October 2025, Governor Gavin Newsom signed AB 1043, a new law for OS providers in California. This law requires an OS to collect users’ ages or birth dates when they set up their accounts. OS providers then must share this information with app developers through a real-time API.
The law divides users into four age groups: under 13, 13-16, 16-18, and 18 and over. Currently, it defines “operating system provider” as anyone who develops, licenses, or maintains operating system software. This includes companies that make Windows, macOS, Android, iOS, Linux distributions, and Valve’s SteamOS.
But the Linux community is overwhelmingly against applying the law to open-source operating systems. Critics have said it would be very hard to enforce rules for community-run distributions such as Ubuntu and Debian. These systems don’t have a central account system and let users download ISO files from various mirrors around the world.
The amended version of the law, called AB 1856, changes the definition of “operating system provider.” Now, it does not include anyone who shares an operating system with terms that allow others to copy, share, and change the software. This change applies to most Linux distributions that use permissive or copyleft licenses.
Proprietary operating systems like Windows, macOS, Android, and iOS will remain subject to these requirements. Valve’s SteamOS will likely still be affected, despite being a Linux-based OS, because the proprietary Steam client functions as a covered application store.
AB 1856 is “currently moving through California’s legislature ahead of committee reviews in June,” Tom’s Hardware reports.
