# CNO26 vs P51

The clearest difference is update cadence: P51 at every 2 weeks against CNO26's every 4 months. P51 also leads on iOS requirement (11.0 vs 15.1). 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.

CNO26 ships an update every 4 months, P51 every 2 weeks. The most recent releases landed on September 10, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | CNO26 | P51 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 weeks** |
| Size | 32 MB | 45 MB |
| Requires iOS | 15.1 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 17+ |
| Developer | [Consejo Argentino de Oftalmología](https://appshunter.io/developer/1591965938) | [SPOTTERON Gmbh](https://appshunter.io/developer/1378099707) |

## What reviewers say

### CNO26

[App page](https://appshunter.io/ios/app/cno26/id1591965936)

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

**In-app purchases:** none


### P51

[App page](https://appshunter.io/ios/app/p51/id6523432516)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CNO26 free?

CNO26 is free to download, with no in-app purchases.

### Is P51 free?

P51 is free to download, with no in-app purchases.

### Do CNO26 or P51 have ads?

Neither CNO26 nor P51 shows ads.

### Which is updated more often, CNO26 or P51?

CNO26 ships an update every 4 months, and P51 every 2 weeks. Most recently, CNO26 was updated on September 10, 2026 and P51 on September 16, 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.*