# siro 公式アプリ vs PrepNote

The clearest difference is in-app purchases: siro 公式アプリ at none against PrepNote's 1. siro 公式アプリ also leads on ads (none vs shown) and iOS requirement (12.0 vs 17.5). PrepNote's advantage is update cadence (every 7 months vs every 39 months). On price and device support there is nothing between them.

Both are free to download. PrepNote sells 1 one-off in-app purchase. siro 公式アプリ asks for nothing beyond the download.

siro 公式アプリ ships an update every 39 months, PrepNote every 7 months. The most recent releases landed on September 15, 2026 and September 14, 2026 respectively.

## The numbers

| Metric | siro 公式アプリ | PrepNote |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 39 months | **Every 7 months** |
| Size | 31 MB | 7 MB |
| Requires iOS | **12.0** | 17.5 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [TAKATOSHI MORIHIRO](https://appshunter.io/developer/1606652618) | [Eri Tominaga](https://appshunter.io/developer/1528527513) |

## What reviewers say

### siro 公式アプリ

[App page](https://appshunter.io/ios/app/siro/id1606652616)

**In-app purchases:** none


### PrepNote

[App page](https://appshunter.io/ios/app/prepnote/id6648762613)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Features | $1.99 | one-time |


## Frequently asked questions

### Is siro 公式アプリ free?

siro 公式アプリ is free to download, with no in-app purchases.

### Is PrepNote free?

PrepNote is free to download, with in-app purchases available.

### Do siro 公式アプリ or PrepNote have ads?

PrepNote shows ads; siro 公式アプリ does not.

### Which is updated more often, siro 公式アプリ or PrepNote?

siro 公式アプリ ships an update every 39 months, and PrepNote every 7 months. Most recently, siro 公式アプリ was updated on September 15, 2026 and PrepNote on September 14, 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.*