LineageOS (originally resurrected from the ashes of CyanogenMod) is renowned for its ability to breathe new life into older Android devices. A prime example is the recent release of LineageOS 16 preview, a ROM designed to bring Android Pie to devices that have ceased receiving official Android updates. Thirty initially supported models, primarily equipped with hardware from 2014, such as the Samsung Galaxy S5 and OnePlus One, are included in this release.
Download and update LineageOS 16 here.
Newer devices can also make use of LineageOS, such as Huawei's P20 Pro, Samsung's Galaxy Tab S2 2016 tablet, and Xiaomi's Pocophone F1.
Expansion of LineageOS support is currently underway. Moreover, there are indications that LineageOS will likely be compatible with Dark Mode on Android in the future.
As usual, for those who want to experience the new features of the update, they can install the preview version, or if not, they can wait until LineageOS 16 is officially released.