Blastoidea From the official FAQs:
When an OEM is no longer providing security updates, GrapheneOS aims to provide harm reduction releases for devices which only have a minimum of 3 years support. Extended support updates at minimum will be done until the next Android version. It is likely that we will make a decision around harm reduction releases for other devices with longer lifetimes in Q4 2024. Harm reduction releases do not have complete security patches because it's not possible to provide full security updates for the device without OEM support and they are intended to buy users some limited time to migrate to a supported device.
The following devices are end-of-life, no longer receive firmware or most driver security updates and receive extended support from GrapheneOS as part of the main releases with all GrapheneOS changes including all of the latest Android Open Source Project changes:
Pixel 5 (redfin)
Pixel 4a (5G) (bramble)
The following devices are end-of-life, no longer receive firmware or driver security updates and receive extended support from GrapheneOS via a legacy branch based on Android 13 with only the Android Open Source Project security backports, certain other security patches and other minimal changes to keep them working:
Pixel 4a (sunfish)
Pixel 4 XL (coral)
Pixel 4 (flame)
We provide extended support releases as a stopgap for users to transition to the far more secure current generation devices.