# SIIM Events vs KOOS

The clearest difference is update cadence: KOOS at weekly against SIIM Events's every 13 months. 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.

SIIM Events ships an update every 13 months, KOOS weekly. Both last shipped on October 27, 2026.

## The numbers

| Metric | SIIM Events | KOOS |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 13 months | **Weekly** |
| Size | 82 MB | 16 MB |
| Requires iOS | 14.0 | 14.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Society for Imaging Informatics in Medicine](https://appshunter.io/developer/1374530516) | [Programmable Equity OU](https://appshunter.io/developer/1685180939) |

## What reviewers say

### SIIM Events

[App page](https://appshunter.io/ios/app/siim-events/id1621274923)

**Features:** macOS Compatibility

**In-app purchases:** none


### KOOS

[App page](https://appshunter.io/ios/app/koos/id6449426162)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SIIM Events free?

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

### Is KOOS free?

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

### Do SIIM Events or KOOS have ads?

Neither SIIM Events nor KOOS shows ads.

### Which is updated more often, SIIM Events or KOOS?

SIIM Events ships an update every 13 months, and KOOS weekly. Most recently, SIIM Events was updated on October 27, 2026 and KOOS on October 27, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*