# Udan HESS vs BisonAuthy

The clearest difference is update cadence: BisonAuthy at every 3 weeks against Udan HESS's every 3 months. Udan HESS's advantage is iOS requirement (13.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

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

Udan HESS ships an update every 3 months, BisonAuthy every 3 weeks. The most recent releases landed on September 28, 2026 and October 2, 2026 respectively.

## The numbers

| Metric | Udan HESS | BisonAuthy |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Size | 33 MB | 5 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Anhui Udan Technology Co., Ltd.](https://appshunter.io/developer/1593792520) | [B&A Group Limited](https://appshunter.io/developer/1821851165) |

## What reviewers say

### Udan HESS

[App page](https://appshunter.io/ios/app/udan-hess/id6443758347)

**Features:** macOS Compatibility

**In-app purchases:** none


### BisonAuthy

[App page](https://appshunter.io/ios/app/bisonauthy/id6499211300)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Udan HESS free?

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

### Is BisonAuthy free?

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

### Do Udan HESS or BisonAuthy have ads?

Neither Udan HESS nor BisonAuthy shows ads.

### Which is updated more often, Udan HESS or BisonAuthy?

Udan HESS ships an update every 3 months, and BisonAuthy every 3 weeks. Most recently, Udan HESS was updated on September 28, 2026 and BisonAuthy on October 2, 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.*