# ZDT vs Tetra Performance Training

The clearest difference is update cadence: Tetra Performance Training at every 2 months against ZDT's every 25 months. Tetra Performance Training also leads on device support. On price, in-app purchases and iOS requirement there is nothing between them.

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

ZDT ships an update every 25 months, Tetra Performance Training every 2 months. The most recent releases landed on October 5, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | ZDT | Tetra Performance Training |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | — | No |
| Update frequency | Every 25 months | **Every 2 months** |
| Size | 48 MB | 42 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | — | **iPhone, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Zachariah Dodge](https://appshunter.io/developer/1705070567) | [David Jarrett](https://appshunter.io/developer/6785643020) |

## What reviewers say

### ZDT

[App page](https://appshunter.io/ios/app/zdt-online/id6463812665)

**In-app purchases:** none


### Tetra Performance Training

[App page](https://appshunter.io/ios/app/tetra-performance-training/id6785643018)

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

**In-app purchases:** none


## Frequently asked questions

### Is ZDT free?

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

### Is Tetra Performance Training free?

Tetra Performance Training is free to download, with no in-app purchases.

### Which is updated more often, ZDT or Tetra Performance Training?

ZDT ships an update every 25 months, and Tetra Performance Training every 2 months. Most recently, ZDT was updated on October 5, 2026 and Tetra Performance Training on October 6, 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.*