# Sustainability Rewards vs UnDoubt

The clearest difference is update cadence: UnDoubt at every 3 weeks against Sustainability Rewards's every 2 months. 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.

Sustainability Rewards ships an update every 2 months, UnDoubt every 3 weeks. The most recent releases landed on October 27, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Sustainability Rewards | UnDoubt |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Size | 66 MB | 85 MB |
| Requires iOS | 15.1 | 15.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Green Rewards Ltd](https://appshunter.io/developer/909021443) | [LastingAsset LIMITED](https://appshunter.io/developer/1738214324) |

## What reviewers say

### Sustainability Rewards

[App page](https://appshunter.io/ios/app/sustainability-rewards/id6475683833)

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

**In-app purchases:** none


### UnDoubt

[App page](https://appshunter.io/ios/app/undoubt/id6744068879)

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

**In-app purchases:** none


## Frequently asked questions

### Is Sustainability Rewards free?

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

### Is UnDoubt free?

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

### Do Sustainability Rewards or UnDoubt have ads?

Neither Sustainability Rewards nor UnDoubt shows ads.

### Which is updated more often, Sustainability Rewards or UnDoubt?

Sustainability Rewards ships an update every 2 months, and UnDoubt every 3 weeks. Most recently, Sustainability Rewards was updated on October 27, 2026 and UnDoubt on October 28, 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.*