One key feature of KernelCare's offering is that it is able to patch systems without the need to reboot. Another is that it claims to deliver most patches faster than they are made available via enterprise Linux updates.
And that's made the Raspberry Pi a tempting target for hackers and other online ne'er-do-wells.
Having developed the technology and infrastructure needed to deliver patches automatically and practically invisibly, KernelCare is now making it available to Raspberry Pi hobbyists at no charge.
Initial support is for the BCM2711 (used in the Pi 4) and BCM2837 (Pi 3 plus later Pi 2 models) running Ubuntu Focal Fossa for 64-bit ARM.
Debian and Raspbian support is coming soon.
Licences can be requested here, with a limit of one licence per email address. That's not one licence per person, as KernelCare notes "If you have multiple Raspberry Pi devices - feel free to register with different email addresses."
The restriction seems to be to make it difficult for commercial users to abuse the offer instead of becoming paying customers. They are offered a free proof of concept with some assistance from KernelCare.