# Z21Updater vs EHEIM Digital Connect

The clearest difference is rating: Z21Updater at 5.0 against EHEIM Digital Connect's 1.7. Z21Updater also leads on review sentiment (50% vs 15%). EHEIM Digital Connect's advantage is update cadence (every 5 weeks vs every 28 months) and ratings volume (12 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Z21Updater holds the better App Store score, 5.0 against 1.7. That said, the two scores are not equally well evidenced: EHEIM Digital Connect has 12 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 50% of Z21Updater's written reviews are positive against 15% of EHEIM Digital Connect's.

Z21Updater ships an update every 28 months, EHEIM Digital Connect every 5 weeks. Both last shipped on October 24, 2026.

## The numbers

| Metric | Z21Updater | EHEIM Digital Connect |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/z21updater/id1463533460/reviews)** | [1.7 (12 ratings)](https://appshunter.io/ios/app/eheim-digital-connect/id6501949799/reviews) |
| Number of ratings | 1 | **12** |
| Positive reviews | **50.0% of reviews** | 14.8% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 28 months | **Every 5 weeks** |
| Monetization | Free | Free |
| Size | 29 MB | 47 MB |
| Requires iOS | 13.4 | **13.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Modelleisenbahn GmbH](https://appshunter.io/developer/533805542) | [Eheim GmbH & Co. KG](https://appshunter.io/developer/888209218) |

## What reviewers say

### Z21Updater

[App page](https://appshunter.io/ios/app/z21updater/id1463533460)

Easily update your Z21, z21, z21start, and smartRail devices. The app automatically detects connected hardware and fetches the latest firmware directly from the server when online, simplifying the update process.

**Highlights:** Automatic device recognition, Direct server updates, Simple and functional update process, Supports Z21, z21, z21start, smartRail

**In-app purchases:** none


### EHEIM Digital Connect

[App page](https://appshunter.io/ios/app/eheim-digital-connect/id6501949799)

This app allows you to connect, set up, and manage various EHEIM digital aquarium devices from your smartphone or tablet. Customize settings for optimal results and ensure your devices are always up-to-date for a thriving aquatic environment.

**Highlights:** Connect and manage digital aquarium devices, Customize device settings, Update device firmware, Control filters, lighting, heaters, and more, Monitor aquarium components

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

**In-app purchases:** none


## Frequently asked questions

### Is Z21Updater free?

Z21Updater is free to download, with no in-app purchases.

### Is EHEIM Digital Connect free?

EHEIM Digital Connect is free to download, with no in-app purchases.

### Which has better reviews, Z21Updater or EHEIM Digital Connect?

Z21Updater is rated higher. Z21Updater averages 5.0 out of 5 from 1 ratings, while EHEIM Digital Connect averages 1.7 from 12 ratings.

### Do Z21Updater or EHEIM Digital Connect have ads?

Neither Z21Updater nor EHEIM Digital Connect shows ads.

### Which is updated more often, Z21Updater or EHEIM Digital Connect?

Z21Updater ships an update every 28 months, and EHEIM Digital Connect every 5 weeks. Most recently, Z21Updater was updated on October 24, 2026 and EHEIM Digital Connect on October 24, 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.*