# Sereniby vs U

The clearest difference is ads: Sereniby at none against U's shown. Sereniby also leads on update cadence (every 3 weeks vs every 2 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Sereniby ships an update every 3 weeks, U every 2 months. The most recent releases landed on October 1, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Sereniby | U |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.8 (5 ratings)](https://appshunter.io/ios/app/sereniby/id6569216382/reviews)** | — |
| Number of ratings | **5** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Monetization | Free | — |
| Size | 116 MB | 66 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Sereniby, Inc.](https://appshunter.io/developer/1758798147) | [Fuzhou Ulandpower Technology Co., Ltd.](https://appshunter.io/developer/1772863390) |

## What reviewers say

### Sereniby

[App page](https://appshunter.io/ios/app/sereniby/id6569216382)

Control your smart air purifier remotely, monitor your baby's room environment in real-time, and receive maintenance alerts. Optimize air quality and comfort with customizable schedules and automatic adjustments for a safe and healthy space.

**Highlights:** Remote smart purifier control, Real-time air quality monitoring, Customizable schedules, Automatic purification adjustments, Maintenance reminders and filter ordering

**In-app purchases:** none


### U

[App page](https://appshunter.io/ios/app/u-flow/id6774060482)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Sereniby free?

Sereniby is free to download, with no in-app purchases.

### Is U free?

U is free to download, with no in-app purchases.

### Do Sereniby or U have ads?

U shows ads; Sereniby does not.

### Which is updated more often, Sereniby or U?

Sereniby ships an update every 3 weeks, and U every 2 months. Most recently, Sereniby was updated on October 1, 2026 and U on October 5, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*