# ECHO vs Sudoku Sagax

The clearest difference is device support: Sudoku Sagax at 3 against ECHO's 1. Sudoku Sagax also leads on iOS requirement (15.0 vs 17.0). 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.

ECHO ships an update every 3 days, Sudoku Sagax every 2 days. The most recent releases landed on October 5, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | ECHO | Sudoku Sagax |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 days | **Every 2 days** |
| Size | 3 MB | 17 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Lucas Hesseldieck](https://appshunter.io/developer/6788079537) | [Vulpes Sagax UG (haftungsbeschränkt)](https://appshunter.io/developer/6806632743) |

## What reviewers say

### ECHO

[App page](https://appshunter.io/ios/app/echo-time-loop-puzzle/id6791749935)

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

**In-app purchases:** none


### Sudoku Sagax

[App page](https://appshunter.io/ios/app/sudoku-sagax/id6806632741)

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

**In-app purchases:** none


## Frequently asked questions

### Is ECHO free?

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

### Is Sudoku Sagax free?

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

### Do ECHO or Sudoku Sagax have ads?

Neither ECHO nor Sudoku Sagax shows ads.

### Which is updated more often, ECHO or Sudoku Sagax?

ECHO ships an update every 3 days, and Sudoku Sagax every 2 days. Most recently, ECHO was updated on October 5, 2026 and Sudoku Sagax on October 18, 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.*