# KAI FLY vs Lumen Viewer

The clearest difference is update cadence: Lumen Viewer at every 2 months against KAI FLY's every 6 months. KAI FLY's advantage is iOS requirement (12.0 vs 17.6). 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.

KAI FLY ships an update every 6 months, Lumen Viewer every 2 months. Both last shipped on October 24, 2026.

## The numbers

| Metric | KAI FLY | Lumen Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/kai-fly/id6471225766/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 2 months** |
| Size | 175 MB | 73 MB |
| Requires iOS | **12.0** | 17.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [荣军 杨](https://appshunter.io/developer/1494250848) | [Steven HAMMOND](https://appshunter.io/developer/973322966) |

## What reviewers say

### KAI FLY

[App page](https://appshunter.io/ios/app/kai-fly/id6471225766)

**Features:** macOS Compatibility

**In-app purchases:** none


### Lumen Viewer

[App page](https://appshunter.io/ios/app/lumen-viewer/id6760626963)

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

**In-app purchases:** none


## Frequently asked questions

### Is KAI FLY free?

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

### Is Lumen Viewer free?

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

### Do KAI FLY or Lumen Viewer have ads?

Neither KAI FLY nor Lumen Viewer shows ads.

### Which is updated more often, KAI FLY or Lumen Viewer?

KAI FLY ships an update every 6 months, and Lumen Viewer every 2 months. Most recently, KAI FLY was updated on October 24, 2026 and Lumen Viewer on October 24, 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.*