# OS vs Strong Challenge

The clearest difference is device support: Strong Challenge at 4 against OS's 2. OS's advantage is iOS requirement (13.5 vs 15.1). On price, update cadence, ads and in-app purchases there is nothing between them.

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

OS ships an update every 3 months, Strong Challenge every 2 months. Both last shipped on November 8, 2026.

## The numbers

| Metric | OS | Strong Challenge |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 2 months** |
| Size | 14 MB | 188 MB |
| Requires iOS | **13.5** | 15.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [OS ONE FITNESS LLC](https://appshunter.io/developer/1784209502) | [Strong Pilates Global Pty Ltd](https://appshunter.io/developer/1484107663) |

## What reviewers say

### OS

[App page](https://appshunter.io/ios/app/os-1-gym/id6739205187)

**Features:** macOS Compatibility

**In-app purchases:** none


### Strong Challenge

[App page](https://appshunter.io/ios/app/strong-challenge/id6748158902)

**Features:** Apple Wallet, Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is OS free?

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

### Is Strong Challenge free?

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

### Do OS or Strong Challenge have ads?

Neither OS nor Strong Challenge shows ads.

### Which is updated more often, OS or Strong Challenge?

OS ships an update every 3 months, and Strong Challenge every 2 months. Most recently, OS was updated on November 8, 2026 and Strong Challenge on November 8, 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.*