# Kernel 背單字 vs ppotaa

The clearest difference is update cadence: Kernel 背單字 at weekly against ppotaa's every 3 weeks. ppotaa's advantage is iOS requirement (15.0 vs 17.0). 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.

Kernel 背單字 ships an update weekly, ppotaa every 3 weeks. The most recent releases landed on September 19, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | Kernel 背單字 | ppotaa |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (1 ratings)](https://appshunter.io/ios/app/ppotaa/id6777933743/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | **Weekly** | Every 3 weeks |
| Monetization | — | Free with in-app purchases |
| Size | 63 MB | 79 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Egan Bisma](https://appshunter.io/developer/1882424495) | [Fluffy Lab](https://appshunter.io/developer/6777933745) |

## What reviewers say

### Kernel 背單字

[App page](https://appshunter.io/ios/app/kernel/id6760036064)

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

**In-app purchases:** none


### ppotaa

[App page](https://appshunter.io/ios/app/ppotaa/id6777933743)

This app helps you build study habits by connecting you with friends in virtual classrooms. Track your progress, customize your avatar, and stay motivated with rewards and a mood calendar.

**Highlights:** Social study rooms with friends, Study time tracking by subject, Daily, weekly, monthly stats, To-do list management, Mood calendar and satisfaction logging, Character and desk customization, Study streak and star rewards

**In-app purchases:** none


## Frequently asked questions

### Is Kernel 背單字 free?

Kernel 背單字 is free to download, with no in-app purchases.

### Is ppotaa free?

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

### Do Kernel 背單字 or ppotaa have ads?

Both Kernel 背單字 and ppotaa show ads.

### Which is updated more often, Kernel 背單字 or ppotaa?

Kernel 背單字 ships an update weekly, and ppotaa every 3 weeks. Most recently, Kernel 背單字 was updated on September 19, 2026 and ppotaa on September 23, 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.*