# Prometheus Mobile STO vs Arrk

The clearest difference is update cadence: Arrk at every 3 days against Prometheus Mobile STO's every 3 months. Prometheus Mobile STO's advantage is device support (3 vs 1) and iOS requirement (11.0 vs 16.4). On price, 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.

Prometheus Mobile STO ships an update every 3 months, Arrk every 3 days. The most recent releases landed on September 14, 2026 and September 11, 2026 respectively.

## The numbers

| Metric | Prometheus Mobile STO | Arrk |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 days** |
| Size | 41 MB | 49 MB |
| Requires iOS | **11.0** | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [PROMETHEUS GROUP, INC.](https://appshunter.io/developer/1554172551) | [Alessandro Mazzon](https://appshunter.io/developer/6800514553) |

## What reviewers say

### Prometheus Mobile STO

[App page](https://appshunter.io/ios/app/prometheus-mobile-sto/id6452803445)

**Features:** macOS Compatibility

**In-app purchases:** none


### Arrk

[App page](https://appshunter.io/ios/app/arrk/id6800514551)

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

**In-app purchases:** none


## Frequently asked questions

### Is Prometheus Mobile STO free?

Prometheus Mobile STO is free to download, with no in-app purchases.

### Is Arrk free?

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

### Do Prometheus Mobile STO or Arrk have ads?

Neither Prometheus Mobile STO nor Arrk shows ads.

### Which is updated more often, Prometheus Mobile STO or Arrk?

Prometheus Mobile STO ships an update every 3 months, and Arrk every 3 days. Most recently, Prometheus Mobile STO was updated on September 14, 2026 and Arrk on September 11, 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.*