Now that DivestOS is discontinued, it’s possible another project will take on their goal of harm reduction for end-of-life devices. DivestOS was started before Treble, Generic Kernel Images and other improvements making device support far easier. A new project should avoid being based on LineageOS.
DivestOS inherited a lot of security and stability regressions from LineageOS. It also meant they ended up with a lot of questionable features they didn’t really want. They ported over a small subset of GrapheneOS privacy and security features. A newer project could port current GrapheneOS instead.
We aren’t going to support insecure devices without proper security patches for firmware/drivers. We also don’t plan to support devices without important security features we need to properly defend users (https://grapheneos.org/faq#future-devices). Still possible to do a port with partial features elsewhere.
DivestOS didn’t have that option initially and was stuck on the path they chose since many of the devices they supported needed it. It didn’t end up going past Android 13 or supporting more recent devices. A project extending the life of devices recently reaching end-of-life can just rely on Treble.
We’d also recommend using the adevtool project maintained as part of GrapheneOS:https://github.com/GrapheneOS/adevtool. It’s now a GrapheneOS project but was previously a ProtonAOSP project before it was discontinued. We were collaborating with them and they did a fair bit of paid work on GrapheneOS.
Oh wow, I never used their ROM but I used Mull exclusively until I switched over to GrapheneOS.