# PSIS Mobile vs PSIS4

The clearest difference is update cadence: PSIS Mobile at every 4 months against PSIS4's every 20 months. PSIS Mobile also leads on device support. On price, in-app purchases and iOS requirement there is nothing between them.

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

PSIS Mobile ships an update every 4 months, PSIS4 every 20 months. The most recent releases landed on September 19, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | PSIS Mobile | PSIS4 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | — |
| Update frequency | **Every 4 months** | Every 20 months |
| Size | 33 MB | 30 MB |
| Requires iOS | 15.1 | 15.1 |
| Devices | **iPhone, iPad, iPod** | — |
| Age rating | 4+ | 4+ |
| Developer | [Sokheng Yong](https://appshunter.io/developer/1633787493) | [YONG SOKHENG](https://appshunter.io/developer/1702023342) |

## What reviewers say

### PSIS Mobile

[App page](https://appshunter.io/ios/app/psis-mobile/id1633787491)

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

**In-app purchases:** none


### PSIS4

[App page](https://appshunter.io/ios/app/psis4/id6460007747)

**In-app purchases:** none


## Frequently asked questions

### Is PSIS Mobile free?

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

### Is PSIS4 free?

PSIS4 is free to download, with no in-app purchases.

### Which is updated more often, PSIS Mobile or PSIS4?

PSIS Mobile ships an update every 4 months, and PSIS4 every 20 months. Most recently, PSIS Mobile was updated on September 19, 2026 and PSIS4 on September 7, 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.*