# MERS.HK vs protostar

The clearest difference is in-app purchases: MERS.HK at none against protostar's 1. MERS.HK also leads on ads (none vs shown). protostar's advantage is update cadence (every 3 weeks vs every 5 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. protostar sells 1 one-off in-app purchase. MERS.HK asks for nothing beyond the download.

MERS.HK ships an update every 5 months, protostar every 3 weeks. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | MERS.HK | protostar |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/protostar/id1504821938/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 40.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 5 months | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 2 MB | 155 MB |
| Requires iOS | 10.0 | 10 |
| Devices | iPad | iPad |
| Age rating | 4+ | 4+ |
| Developer | [Modern Educational Research Society, LTD](https://appshunter.io/developer/432268704) | [Longzhe Education Technology (Shanghai) Co., Ltd.](https://appshunter.io/developer/1504821937) |

## What reviewers say

### MERS.HK

[App page](https://appshunter.io/ios/app/mershk/id555592128)

This app provides students and teachers with an optimized experience for accessing and interacting with e-learning resources. Users can annotate screenshots, seamlessly connect with other educational tools, and enjoy a locked rotation for comfortable viewing.

**Highlights:** Optimized viewing and access to e-learning resources, Screenshot annotation and sharing, Seamless integration with other MERS apps, Automatic rotation lock for comfortable use, Designed for MERS e-Learning in Schools partners

**In-app purchases:** none


### protostar

[App page](https://appshunter.io/ios/app/protostar/id1504821938)

This educational app is designed for students aged 7-12, offering a platform for watching learning videos and playing interactive games. It is exclusively for users of the protostar education company and is available on iPad.

**Highlights:** Learning videos, Educational games, Preview content, Review content, Designed for ages 7-12

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Protostar English Course | $299.99 | one-time |


## Frequently asked questions

### Is MERS.HK free?

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

### Is protostar free?

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

### Do MERS.HK or protostar have ads?

protostar shows ads; MERS.HK does not.

### Which is updated more often, MERS.HK or protostar?

MERS.HK ships an update every 5 months, and protostar every 3 weeks. Most recently, MERS.HK was updated on November 1, 2026 and protostar on November 3, 2026.

---

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