# Sudoku vs Quiet Letters

The clearest difference is in-app purchases: Quiet Letters at none against Sudoku's 2. Quiet Letters also leads on ads (none vs shown). Sudoku's advantage is update cadence (every 3 days vs every 3 weeks). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Sudoku sells 2 one-off in-app purchases. Quiet Letters asks for nothing beyond the download.

Sudoku ships an update every 3 days, Quiet Letters every 3 weeks. The most recent releases landed on October 28, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Sudoku | Quiet Letters |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 3 weeks |
| Size | 147 MB | 44 MB |
| Requires iOS | **16.0** | 17.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [KUO CHENG-YEN](https://appshunter.io/developer/1875151535) | [Laurent Chouinard](https://appshunter.io/developer/1896321782) |

## What reviewers say

### Sudoku

[App page](https://appshunter.io/ios/app/sudoku-notes-games/id6760650479)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| bone | $0.99 | one-time |
| Unlock perks | $2.99 | one-time |


### Quiet Letters

[App page](https://appshunter.io/ios/app/quiet-letters/id6766751256)

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

**In-app purchases:** none


## Frequently asked questions

### Is Sudoku free?

Sudoku is free to download, with in-app purchases available.

### Is Quiet Letters free?

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

### Do Sudoku or Quiet Letters have ads?

Sudoku shows ads; Quiet Letters does not.

### Which is updated more often, Sudoku or Quiet Letters?

Sudoku ships an update every 3 days, and Quiet Letters every 3 weeks. Most recently, Sudoku was updated on October 28, 2026 and Quiet Letters on October 31, 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.*