# Xkey Plus vs Guitar Permutation Trainer

The clearest difference is price: Xkey Plus at Free against Guitar Permutation Trainer's $1.99. Xkey Plus also leads on iOS requirement (9.3 vs 18.4). Guitar Permutation Trainer's advantage is update cadence (every 3 days vs every 3 months). On ads, in-app purchases and device support there is nothing between them.

Xkey Plus is free to download; Guitar Permutation Trainer costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Xkey Plus ships an update every 3 months, Guitar Permutation Trainer every 3 days. The most recent releases landed on September 24, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Xkey Plus | Guitar Permutation Trainer |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | **[2.9 (13 ratings)](https://appshunter.io/ios/app/xkey-plus/id698087460/reviews)** | — |
| Number of ratings | **13** | — |
| Positive reviews | 35.7% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 days** |
| Monetization | Free | — |
| Size | 9 MB | 3 MB |
| Requires iOS | **9.3** | 18.4 |
| Devices | iPad | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [ESI Audiotechnik GmbH](https://appshunter.io/developer/1627424644) | [Benjamin Chouinard](https://appshunter.io/developer/1826188450) |

## What reviewers say

### Xkey Plus

[App page](https://appshunter.io/ios/app/xkey-plus/id698087460)

This app enhances the functionality of ESI Xkey musical keyboards on mobile devices. It allows users to update firmware, customize velocity curves, and configure key sensitivity and timings for an advanced user experience.

**Highlights:** Check for new Xkey firmware, Velocity curves editor, Configure Xkey sensitivity & timings, Access all Xkey parameters, Configure key & button assignments, Access Xkey documentation & support

**Features:** macOS Compatibility

**In-app purchases:** none


### Guitar Permutation Trainer

[App page](https://appshunter.io/ios/app/guitar-permutation-trainer/id6748545844)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Xkey Plus free?

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

### Is Guitar Permutation Trainer free?

Guitar Permutation Trainer costs $1.99, with no in-app purchases.

### Do Xkey Plus or Guitar Permutation Trainer have ads?

Neither Xkey Plus nor Guitar Permutation Trainer shows ads.

### Which is updated more often, Xkey Plus or Guitar Permutation Trainer?

Xkey Plus ships an update every 3 months, and Guitar Permutation Trainer every 3 days. Most recently, Xkey Plus was updated on September 24, 2026 and Guitar Permutation Trainer on October 10, 2026.

---

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