# simos.app vs D

The clearest difference is device support: D at 3 against simos.app's 1. D also leads on iOS requirement (15.0 vs 17.6). On price, update cadence, ads and in-app purchases there is nothing between them.

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

simos.app ships an update every 4 days, D every 5 days. The most recent releases landed on October 1, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | simos.app | D |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/simosapp/id6760018423/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 5 days |
| Monetization | Free | — |
| Size | 6 MB | 30 MB |
| Requires iOS | 17.6 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Tycho Sebastian Holzer](https://appshunter.io/developer/1882338941) | [LUN LIU](https://appshunter.io/developer/1890125123) |

## What reviewers say

### simos.app

[App page](https://appshunter.io/ios/app/simosapp/id6760018423)

This tool provides diagnostic, data logging, and flashing capabilities for VAG petrol engines with specific Simos ECUs. Monitor real-time engine parameters, analyze recorded sessions with graphs, and update your ECU with stock or custom tunes.

**Highlights:** Real-time ECU parameter monitoring, Live data logging via Bluetooth LE, ECU identification (software/calibration IDs), Multi-channel graph analysis of logged sessions, ECU and TCU flashing (stock and custom tunes), Support for Simos 18.x and 12.1 ECUs

**In-app purchases:** none


### D

[App page](https://appshunter.io/ios/app/d-sync-ecu/id6761677479)

**In-app purchases:** none


## Frequently asked questions

### Is simos.app free?

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

### Is D free?

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

### Do simos.app or D have ads?

Neither simos.app nor D shows ads.

### Which is updated more often, simos.app or D?

simos.app ships an update every 4 days, and D every 5 days. Most recently, simos.app was updated on October 1, 2026 and D 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.*