# airAlert vs Coach Stef

The clearest difference is update cadence: Coach Stef at every 3 weeks against airAlert's every 35 months. airAlert's advantage is iOS requirement (8.0 vs 13.0). 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.

airAlert ships an update every 35 months, Coach Stef every 3 weeks. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | airAlert | Coach Stef |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 35 months | **Every 3 weeks** |
| Size | 29 MB | 418 MB |
| Requires iOS | **8.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Environmental Research Group-King's College London](https://appshunter.io/developer/358970520) | [Outperform Fitness & Marketing GmbH](https://appshunter.io/developer/1550616004) |

## What reviewers say

### airAlert

[App page](https://appshunter.io/ios/app/airalert/id991737402)

**Features:** macOS Compatibility

**In-app purchases:** none


### Coach Stef

[App page](https://appshunter.io/ios/app/coach-stef/id6755230559)

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

**In-app purchases:** none


## Frequently asked questions

### Is airAlert free?

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

### Is Coach Stef free?

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

### Do airAlert or Coach Stef have ads?

Neither airAlert nor Coach Stef shows ads.

### Which is updated more often, airAlert or Coach Stef?

airAlert ships an update every 35 months, and Coach Stef every 3 weeks. Most recently, airAlert was updated on October 24, 2026 and Coach Stef on October 25, 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.*