# MBS Checkin Trainer vs 21 Days Challenge

The clearest difference is iOS requirement: 21 Days Challenge at 13.0 against MBS Checkin Trainer's 15.6. 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.

MBS Checkin Trainer ships an update every 2 weeks, 21 Days Challenge every 10 days. The most recent releases landed on November 3, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | MBS Checkin Trainer | 21 Days Challenge |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 10 days** |
| Size | 56 MB | 46 MB |
| Requires iOS | 15.6 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 12+ |
| Developer | [Ha Hung Phi](https://appshunter.io/developer/1639679625) | [Tung Bui Thanh](https://appshunter.io/developer/1504830403) |

## What reviewers say

### MBS Checkin Trainer

[App page](https://appshunter.io/ios/app/mbs-checkin-trainer/id1639712894)

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

**In-app purchases:** none


### 21 Days Challenge

[App page](https://appshunter.io/ios/app/21-days-challenge/id6753333556)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is MBS Checkin Trainer free?

MBS Checkin Trainer is free to download, with no in-app purchases.

### Is 21 Days Challenge free?

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

### Do MBS Checkin Trainer or 21 Days Challenge have ads?

Neither MBS Checkin Trainer nor 21 Days Challenge shows ads.

### Which is updated more often, MBS Checkin Trainer or 21 Days Challenge?

MBS Checkin Trainer ships an update every 2 weeks, and 21 Days Challenge every 10 days. Most recently, MBS Checkin Trainer was updated on November 3, 2026 and 21 Days Challenge 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.*