# Preview App vs Knockbox

The clearest difference is price: Knockbox at Free against Preview App's $1.99. Knockbox also leads on update cadence (daily vs every 13 months). Preview App's advantage is iOS requirement (15.6 vs 17.0). On ads, in-app purchases and device support there is nothing between them.

Knockbox is free to download; Preview App costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Preview App ships an update every 13 months, Knockbox daily. The most recent releases landed on October 8, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Preview App | Knockbox |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 13 months | **Daily** |
| Size | 8 MB | 7 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Cangmu Technology Co., Ltd](https://appshunter.io/developer/1736424342) | [苗 苗](https://appshunter.io/developer/6791624017) |

## What reviewers say

### Preview App

[App page](https://appshunter.io/ios/app/preview-app-store-simulator/id1626025800)

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

**In-app purchases:** none


### Knockbox

[App page](https://appshunter.io/ios/app/knockbox-self-hosted-push/id6811317906)

**In-app purchases:** none


## Frequently asked questions

### Is Preview App free?

Preview App costs $1.99, with no in-app purchases.

### Is Knockbox free?

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

### Do Preview App or Knockbox have ads?

Neither Preview App nor Knockbox shows ads.

### Which is updated more often, Preview App or Knockbox?

Preview App ships an update every 13 months, and Knockbox daily. Most recently, Preview App was updated on October 8, 2026 and Knockbox on October 6, 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.*