# mos.viewer vs INCHSTONE OPC Browser

The clearest difference is iOS requirement: mos.viewer at 13.0 against INCHSTONE OPC Browser's 15.0. On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

mos.viewer ships an update every 4 months, INCHSTONE OPC Browser every 3 months. The most recent releases landed on September 11, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | mos.viewer | INCHSTONE OPC Browser |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 months** |
| Size | 23 MB | 131 MB |
| Requires iOS | **13.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Fabrik 19 AG](https://appshunter.io/developer/501964744) | [INCHSTONE GmbH](https://appshunter.io/developer/1480423246) |

## What reviewers say

### mos.viewer

[App page](https://appshunter.io/ios/app/mosviewer/id6470921065)

**In-app purchases:** none


### INCHSTONE OPC Browser

[App page](https://appshunter.io/ios/app/inchstone-opc-browser/id6599836514)

**In-app purchases:** none


## Frequently asked questions

### Is mos.viewer free?

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

### Is INCHSTONE OPC Browser free?

INCHSTONE OPC Browser is free to download, with no in-app purchases.

### Do mos.viewer or INCHSTONE OPC Browser have ads?

Neither mos.viewer nor INCHSTONE OPC Browser shows ads.

### Which is updated more often, mos.viewer or INCHSTONE OPC Browser?

mos.viewer ships an update every 4 months, and INCHSTONE OPC Browser every 3 months. Most recently, mos.viewer was updated on September 11, 2026 and INCHSTONE OPC Browser on September 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.*