# Progressive Overload Training vs AI Letter

The clearest difference is in-app purchases: AI Letter at none against Progressive Overload Training's 2. AI Letter also leads on update cadence (every 3 days vs weekly) and iOS requirement (15.1 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. Progressive Overload Training sells 2 in-app purchases, starting at $0.99 per month. AI Letter asks for nothing beyond the download.

Progressive Overload Training ships an update weekly, AI Letter every 3 days. The most recent releases landed on October 4, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Progressive Overload Training | AI Letter |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Weekly | **Every 3 days** |
| Size | 17 MB | 28 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Muhammad Hassan](https://appshunter.io/developer/1249312001) | [KKANG'S LAB](https://appshunter.io/developer/1122663875) |

## What reviewers say

### Progressive Overload Training

[App page](https://appshunter.io/ios/app/progressive-overload-training/id6460368757)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Provtra Monthly Pro | $0.99 | per month |
| Provtra Yearly Pro | $9.99 | per year |


### AI Letter

[App page](https://appshunter.io/ios/app/ai-letter-write-and-share/id6757287624)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Progressive Overload Training free?

Progressive Overload Training is free to download, with in-app purchases available.

### Is AI Letter free?

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

### Do Progressive Overload Training or AI Letter have ads?

Both Progressive Overload Training and AI Letter show ads.

### Which is updated more often, Progressive Overload Training or AI Letter?

Progressive Overload Training ships an update weekly, and AI Letter every 3 days. Most recently, Progressive Overload Training was updated on October 4, 2026 and AI Letter on October 12, 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.*