# BTR_OCC vs BU01 Reader

The clearest difference is iOS requirement: BU01 Reader at 9.0 against BTR_OCC's 12.0. 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.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on September 29, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | BTR_OCC | BU01 Reader |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Size | 15 MB | 1 MB |
| Requires iOS | 12.0 | **9.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [acv](https://appshunter.io/developer/1240641582) | [育明 李](https://appshunter.io/developer/572761656) |

## What reviewers say

### BTR_OCC

[App page](https://appshunter.io/ios/app/btr-occ/id1407539259)

**Features:** macOS Compatibility

**In-app purchases:** none


### BU01 Reader

[App page](https://appshunter.io/ios/app/bu01-reader/id1435757804)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is BTR_OCC free?

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

### Is BU01 Reader free?

BU01 Reader is free to download, with no in-app purchases.

### Do BTR_OCC or BU01 Reader have ads?

Neither BTR_OCC nor BU01 Reader shows ads.

### Which is updated more often, BTR_OCC or BU01 Reader?

BTR_OCC ships an update every 2 months, and BU01 Reader every 2 months. Most recently, BTR_OCC was updated on September 29, 2026 and BU01 Reader on September 26, 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.*