# KOil vs X

The clearest difference is update cadence: X at every 4 months against KOil's every 38 months. X also leads on device support (3 vs 1) and iOS requirement (12.0 vs 16.6). On price, 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.

KOil ships an update every 38 months, X every 4 months. The most recent releases landed on September 10, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | KOil | X |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 38 months | **Every 4 months** |
| Size | 40 MB | 79 MB |
| Requires iOS | 16.6 | **12.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Khaled Alsalem](https://appshunter.io/developer/1441688302) | [University of Oulu](https://appshunter.io/developer/1057902852) |

## What reviewers say

### KOil

[App page](https://appshunter.io/ios/app/koil/id1446544213)

**Features:** macOS Compatibility

**In-app purchases:** none


### X

[App page](https://appshunter.io/ios/app/x-ray-scatter-sim/id6463718894)

**In-app purchases:** none


## Frequently asked questions

### Is KOil free?

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

### Is X free?

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

### Do KOil or X have ads?

Neither KOil nor X shows ads.

### Which is updated more often, KOil or X?

KOil ships an update every 38 months, and X every 4 months. Most recently, KOil was updated on September 10, 2026 and X on September 18, 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.*