# D1 System vs FD Service

The clearest difference is update cadence: FD Service at monthly against D1 System's every 2 months. D1 System's advantage is iOS requirement (8.0 vs 12.0). 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.

D1 System ships an update every 2 months, FD Service monthly. The most recent releases landed on June 8, 2026 and August 20, 2026 respectively.

## The numbers

| Metric | D1 System | FD Service |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[1.0 (1 ratings)](https://appshunter.io/ios/app/fd-service/id6470879850/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Monthly** |
| Monetization | Free | Free |
| Size | 6 MB | 42 MB |
| Requires iOS | **8.0** | 12.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [China Security & Fire IOT Sensing Co., Ltd.](https://appshunter.io/developer/914724038) | [BYD Auto Industry Company Limited](https://appshunter.io/developer/888165335) |

## What reviewers say

### D1 System

[App page](https://appshunter.io/ios/app/d1-system/id914724035)

This app allows users to remotely manage an SMS alarm system. It enables sending text messages for home protection, configuring alarm host parameters, and setting zone and RFID card names. Users can also manage SMS codes.

**Highlights:** Send SMS for home protection, Configure alarm host parameters, Set zone names, Set RFID card names, Manage SMS codes

**Features:** macOS Compatibility

**In-app purchases:** none


### FD Service

[App page](https://appshunter.io/ios/app/fd-service/id6470879850)

This app manages after-sales service for energy storage products. It handles work orders for customer issues and spare parts inventory, ensuring accurate data and efficient internal and external collaboration.

**Highlights:** Work order management, Spare parts inventory tracking, Customer service integration, Online collaboration, Data management, Material transfer between warehouses

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

**In-app purchases:** none


## Frequently asked questions

### Is D1 System free?

D1 System is free to download, with no in-app purchases.

### Is FD Service free?

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

### Do D1 System or FD Service have ads?

Neither D1 System nor FD Service shows ads.

### Which is updated more often, D1 System or FD Service?

D1 System ships an update every 2 months, and FD Service monthly. Most recently, D1 System was updated on June 8, 2026 and FD Service on August 20, 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.*