If you are specifically looking for the features introduced in the 8.6.2 era, they included:
: If prompted, allow your browser to "Install apps from unknown sources" in your device settings. If you are specifically looking for the features
: Open the downloaded file and follow the prompts. This will typically replace your Play Store version while keeping your chats intact. they included: : If prompted
: An updated look when sending files or media. If you are specifically looking for the features