# Green Hydrogen Solutions vs Dull Grading

The clearest difference is update cadence: Dull Grading at every 2 months against Green Hydrogen Solutions's every 28 months. Dull Grading also leads on iOS requirement (13.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Green Hydrogen Solutions ships an update every 28 months, Dull Grading every 2 months. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.

## The numbers

| Metric | Green Hydrogen Solutions | Dull Grading |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 28 months | **Every 2 months** |
| Size | 11 MB | 44 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Green Hydrogen Solutions](https://appshunter.io/developer/1601781519) | [ZerdaLab Ltd](https://appshunter.io/developer/1694028622) |

## What reviewers say

### Green Hydrogen Solutions

[App page](https://appshunter.io/ios/app/green-hydrogen-solutions/id1613715379)

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

**In-app purchases:** none


### Dull Grading

[App page](https://appshunter.io/ios/app/dull-grading/id6450608130)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Green Hydrogen Solutions free?

Green Hydrogen Solutions is free to download, with no in-app purchases.

### Is Dull Grading free?

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

### Do Green Hydrogen Solutions or Dull Grading have ads?

Neither Green Hydrogen Solutions nor Dull Grading shows ads.

### Which is updated more often, Green Hydrogen Solutions or Dull Grading?

Green Hydrogen Solutions ships an update every 28 months, and Dull Grading every 2 months. Most recently, Green Hydrogen Solutions was updated on October 24, 2026 and Dull Grading on October 27, 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.*