# RR4 Scheduler vs Referee Yellow card, Whistle

The clearest difference is ads: RR4 Scheduler at none against Referee Yellow card, Whistle's shown. RR4 Scheduler also leads on iOS requirement (12.0 vs 15.6). On price, update cadence, in-app purchases and device support there is nothing between them.

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

RR4 Scheduler ships an update every 4 months, Referee Yellow card, Whistle every 2 months. The most recent releases landed on October 27, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | RR4 Scheduler | Referee Yellow card, Whistle |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (52 ratings)](https://appshunter.io/ios/app/referee-yellow-card-whistle/id6449401491/reviews)** |
| Number of ratings | — | **52** |
| Positive reviews | — | 71.4% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | — | Ad-supported |
| Size | 55 MB | 15 MB |
| Requires iOS | **12.0** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Christian Petropolis](https://appshunter.io/developer/1528452853) | [Ryouhei Azuma](https://appshunter.io/developer/1353297781) |

## What reviewers say

### RR4 Scheduler

[App page](https://appshunter.io/ios/app/rr4-scheduler/id1664033101)

**Features:** macOS Compatibility

**In-app purchases:** none


### Referee Yellow card, Whistle

[App page](https://appshunter.io/ios/app/referee-yellow-card-whistle/id6449401491)

This utility app provides a digital referee toolkit for sports and other situations. It features a whistle sound and full-screen display of various colored cards for judgment calls. Designed for simplicity, it's suitable for games, training, or even pranks.

**Highlights:** Whistle sound functionality, Full-screen yellow, red, orange, and green cards, Simple and easy-to-use interface, Suitable for sports refereeing, Useful for training and games, Can be used for pranks

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

**In-app purchases:** none


## Frequently asked questions

### Is RR4 Scheduler free?

RR4 Scheduler is free to download, with no in-app purchases.

### Is Referee Yellow card, Whistle free?

Referee Yellow card, Whistle is free to download, with no in-app purchases.

### Do RR4 Scheduler or Referee Yellow card, Whistle have ads?

Referee Yellow card, Whistle shows ads; RR4 Scheduler does not.

### Which is updated more often, RR4 Scheduler or Referee Yellow card, Whistle?

RR4 Scheduler ships an update every 4 months, and Referee Yellow card, Whistle every 2 months. Most recently, RR4 Scheduler was updated on October 27, 2026 and Referee Yellow card, Whistle 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.*