# Lockoon vs Duet

The clearest difference is ads: Duet at none against Lockoon's shown. Lockoon's advantage is iOS requirement (16.4 vs 27.0). On price, update cadence, in-app purchases and device support there is nothing between them.

Both are free to download. Lockoon sells 1 in-app purchase, starting at $1.99 per year and Duet sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Lockoon ships an update every 3 weeks, Duet every 10 days. Both last shipped on November 10, 2026.

## The numbers

| Metric | Lockoon | Duet |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 3 weeks | **Every 10 days** |
| Size | 44 MB | 31 MB |
| Requires iOS | **16.4** | 27.0 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Erdem Ege Eroglu](https://appshunter.io/developer/1855623817) | [Conscious Engines](https://appshunter.io/developer/1876149587) |

## What reviewers say

### Lockoon

[App page](https://appshunter.io/ios/app/lockoon/id6814609716)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lockoon Pro | $1.99 | per year |


### Duet

[App page](https://appshunter.io/ios/app/duet-pdf-reader/id6821941148)

**Features:** iPhone Duo support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Duet Pro Lifetime | $9.99 | one-time |


## Frequently asked questions

### Is Lockoon free?

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

### Is Duet free?

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

### Do Lockoon or Duet have ads?

Lockoon shows ads; Duet does not.

### Which is updated more often, Lockoon or Duet?

Lockoon ships an update every 3 weeks, and Duet every 10 days. Most recently, Lockoon was updated on November 10, 2026 and Duet on November 10, 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.*