The "16.40.35" designation refers to the version number of the official YouTube app on which the mod is based. This specific build was released around late 2021. A "Mod APK" (Android Package Kit) is a reworked version of the original app that has been decompiled, altered to include new features or remove restrictions, and recompiled for installation.

The 16.40.35 version is particularly notable because it was one of the stable builds widely used by the ReVanced and Vanced teams before major changes in YouTube’s architecture made older mods obsolete. It is essentially a "time capsule" of premium features offered for free.

You might ask, “Why not the latest version 19?” The answer lies in code complexity.

YouTube version 16.40.35 was released before Google implemented obfuscation layers and SafetyNet attestation inside the YouTube app. Later versions (17.0 and above) introduced:

Because 16.40.35 was built on a simpler API, modders found it easy to permanently disable ad servers and unlock background playback without triggering server bans. It became the "final stable" version for many users with older phones (Android 5.0 to 8.0) due to its lightweight nature.

Installing a Mod APK is different from installing an app from the Google Play Store. Users must be aware of the technical and security implications.

It is impossible to discuss the 16.40.35 Mod APK without mentioning MicroG. Because the modded app uses Google Services but isn't officially sanctioned by Google, it cannot sign in with a standard Google account framework.

To sign in to a Mod APK (to access subscriptions and history), users must install a companion app called MicroG. This is a free, open-source implementation of Google Play Services. Without MicroG, the modded app functions as a guest user only.

The most obvious benefit is the removal of all advertisements. This includes pre-roll ads (before the video starts), mid-roll ads (interrupting the video), and banner ads on the home screen.