# Certisep vs LinDuo

The clearest difference is in-app purchases: Certisep at none against LinDuo's 4. Certisep also leads on update cadence (every 2 months vs every 6 months). LinDuo's advantage is iOS requirement (11.0 vs 18.7). On price, ads and device support there is nothing between them.

Both are free to download. LinDuo sells 4 one-off in-app purchases. Certisep asks for nothing beyond the download.

Certisep ships an update every 2 months, LinDuo every 6 months. The most recent releases landed on October 29, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Certisep | LinDuo |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (20 ratings)](https://appshunter.io/ios/app/linduo-learn-russian/id1602896279/reviews)** |
| Number of ratings | — | **20** |
| Positive reviews | — | 85.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 6 months |
| Monetization | — | Free with in-app purchases |
| Size | 114 MB | 278 MB |
| Requires iOS | 18.7 | **11.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Ingenieria Estrategia y Comunicacion en Internet, SC](https://appshunter.io/developer/926911589) | [Vitali Simsive](https://appshunter.io/developer/1247127045) |

## What reviewers say

### Certisep

[App page](https://appshunter.io/ios/app/certisep/id1474307312)

**Features:** Vision Pro support

**In-app purchases:** none


### LinDuo

[App page](https://appshunter.io/ios/app/linduo-learn-russian/id1602896279)

Learn Russian vocabulary with short, engaging lessons. Features native speaker pronunciation, visual aids, and a built-in dictionary. Practice with games and custom lessons designed for quick daily study.

**Highlights:** Native speaker pronunciation, 2375 words in 180 topic lessons, Offline access, Illustrations and phonetic transcriptions, Customizable lessons, Progress tracking dictionary, True or False review game

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Work Offline! | $0.99 | one-time |
| Unlimited Energy! | $4.99 | one-time |
| All Inclusive! | $9.99 | one-time |
| Help the Project! | $29.99 | one-time |


## Frequently asked questions

### Is Certisep free?

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

### Is LinDuo free?

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

### Do Certisep or LinDuo have ads?

Neither Certisep nor LinDuo shows ads.

### Which is updated more often, Certisep or LinDuo?

Certisep ships an update every 2 months, and LinDuo every 6 months. Most recently, Certisep was updated on October 29, 2026 and LinDuo on November 3, 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.*