> ## Content Index
> Fetch the complete content index at: https://www.vacubots.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Eufy Omni S2 Firmware Update Adds Finer Mop Water Control and Slip Detection
- URL: https://www.vacubots.com/eufy-omni-s2-firmware-update-adds-more-mop-water-control-and-slip-detection/
- Published: 2026-09-29T19:12:49.000Z
- Updated: 2026-10-17T03:19:13.000Z
- Description: Eufy firmware v4.2.21 adds finer mop water control, slip detection and fixes for charging alerts and side-brush protection on the Omni S2.
- Author: J Allen, Editor
- Tags: Anker Eufy, Omni S2

Eufy is rolling out firmware version v4.2.21 for the [Omni S2](https://www.vacubots.com/eufy-omni-s2-150-day-review-clever-cyclone-but-a-mopping-downgrade/), adding finer mop water control, slip detection and fixes for charging alerts and side-brush protection.

The firmware arrives alongside a redesigned Anker eufy app with a new logo, updated graphics and revised cleaning controls.

## More Control Over Mop Water

The updated app replaces the S2's previous fixed water levels with a wetness slider that allows finer adjustment.

That directly addresses one of our complaints from long-term testing. The S2 generally left floors drier than the S1 Pro and struggled more with some dried-on stains.

![Anker eufy app showing the Omni S2 water-flow slider set to 43% in the robot vacuum cleaning controls.](https://storage.ghost.io/c/69/d5/69d51699-d072-45ac-9ab4-d45efbe74012/content/images/2026/09/EufyS2FirmwareUpdate.gif)

Eufy’s updated Anker eufy app adds a dynamic water-flow slider for the Omni S2, giving owners finer control over mop wetness than the previous fixed settings.

The new control should make it easier to increase water for tougher messes or reduce it for more sensitive flooring.

## Slip Detection Added

Firmware v4.2.21 also adds a slip detection switch.

According to Eufy, the setting detects when the robot is slipping and adjusts the roller mop to help it keep moving and maintain cleaning coverage.

Eufy does not explain exactly what changes are made to the roller when slipping is detected, so more testing will be needed to see how much difference the setting makes on slick floors.

## Charging and Side-Brush Fixes

The update fixes a false charging alert issue and changes the side brush overcurrent protection strategy.

Eufy does not provide additional details on either change.

Software reliability has been one of the weaker parts of our long-term S2 experience, with previous firmware contributing to mapping issues, scheduled cleaning problems and changes in navigation behavior.

Version v4.2.21 replaces v4.2.3 on our S2.

## Anker eufy App Gets a New Look

The app is now branded Anker eufy and uses a new logo with updated graphics throughout the interface.

The changes are mostly visual, giving the app a refreshed look without significantly changing how S2 owners navigate its controls.

## What We Will Be Watching

The most important question is whether the new controls improve the S2 in actual use.

We will be testing the wetness slider on dried stains in our home using different types of flooring, while also watching whether slip detection improves movement across rugs and transitions.

---