We already know which first few phones are receiving support for the brand-new Android 10-based LineageOS 17.1, but now, the open-source project has released a full changelog and shared why it has decided to make it an x.1 release. The new software is packed with additions such as a partial screenshot functionality, the spiritual successor to the CyanogenMod Theme Engine, Lineage Recovery, and many smaller changes.

Usually, LineageOS version numbers correlate to Android version numbers, so it's odd that Android 10 translates to LineageOS 17.1. In the Changelog 24 blog post, the organization writes that's because it bases its version on the December Pixel feature drop that added new code to the Pixel 4 tag of AOSP. The changes were so significant that the developers had to rebase a large number of repos, so they've decided to go ahead with 17.1. Apart from other notable AOSP code changes from Android 9 to 10, that's also another reason why it took the project so long to launch the new LineageOS.

As always, the blog post wouldn't be complete without an extensive changelog, which you can dive into here:

LineageOS 17.1 new features:
  • A new partial screenshot UI was implemented that lets you hand select smaller parts of your screen and edit the screenshots. So, feel free to go give it a “shot”!
  • We know many of you have been waiting for news on themes since the CyanogenMod Theme Engine’s deprecation in CyanogenMod 13.0, and those of you in this boat are in for a treat!
    • AOSP’s new ThemePicker app was adapted to have the range of accents you’ve become used to with our old implementation, Styles.
    • We also opted to enable support for font change, icon shape (both QuickSettings and Launcher) and icon style changes (eg. changing the style of the Wi-Fi/Bluetooth icons).
  • Trebuchet has long been able to hide apps from the Launcher and protect them with a passcode/password, but now you can also use your biometric sensor to authenticate as well!
  • October, November, December 2019 and January, February, March 2020 security patches have been merged.
    • Builds are currently based on the android-10.0.0_r31 tag, which is the Pixel 4/4 XL’s tag.
  • Wi-Fi display is available once again.
  • Support for on-screen fingerprint sensors (FOD) has been added.
  • Support for pop-up and rotating cameras has been added.
  • Support for Australian English, Lithuanian, Latvian, Dutch, Romanian, Slovenian, Serbian and Turkish spell checking has been added to AOSP keyboard.
  • AOSP keyboard available emojis have been updated to Emoji 12.0.
  • WebView has been updated to Chromium 80.0.3987.132.

Additionally, Lineage Recovery has become the default install solution for the custom ROM — it will be built for all officially supported devices. The TWRP alternative has been in the works since 2018 and should make it easier to support both phones with and without A/B partitions.

There are also some deprecations. The Styles API has been replaced by the ThemePicker app as there is now complete feature parity between the two. LineageOS's signature PrivacyGuard has made way for AOSP's PermissionHub, which is capable of all the things LineageOS's own solution was of. The expanded desktop feature has also been dropped as it clashed with Android 10's navigation gestures. Additionally, it proved difficult to port the software due to restructured code in AOSP.

Check out which phones support the latest release of LineageOS and head to the project's blog if you want to go for a deep dive into all of the granular changes and deprecations and get information on the upgrade process from older versions. The 17.1 branch will receive nightly updates going forward, while the 16.0 release will be moved to weekly builds.