# D vs NIO Zen Smart Lock

D and NIO Zen Smart Lock are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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

D ships an update monthly, NIO Zen Smart Lock every 2 months. The most recent releases landed on September 10, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | D | NIO Zen Smart Lock |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 28.6% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Monthly** | Every 2 months |
| Monetization | — | Free |
| Size | 34 MB | 13 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPod, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [SECUREMME SRL](https://appshunter.io/developer/1076281466) | [Evva Italia srl](https://appshunter.io/developer/1561615007) |

## What reviewers say

### D

[App page](https://appshunter.io/ios/app/d-smart-20/id1483095654)

**Features:** macOS Compatibility

**In-app purchases:** none


### NIO Zen Smart Lock

[App page](https://appshunter.io/ios/app/nio-zen-smart-lock/id1561615005)

This smart lock system offers automatic locking with high-security modular cylinders. It installs on any door without modifications and can be configured via smartphone or dedicated remote. Access is granted through various methods including biometric and RFID.

**Highlights:** Automatic locking, High-security modular cylinders, Easy installation on any door, Smartphone configuration via Bluetooth, Multiple access methods (RFID, biometric, keypad), Access logging and user management, Long-lasting rechargeable batteries

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is D free?

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

### Is NIO Zen Smart Lock free?

NIO Zen Smart Lock is free to download, with no in-app purchases.

### Do D or NIO Zen Smart Lock have ads?

Neither D nor NIO Zen Smart Lock shows ads.

### Which is updated more often, D or NIO Zen Smart Lock?

D ships an update monthly, and NIO Zen Smart Lock every 2 months. Most recently, D was updated on September 10, 2026 and NIO Zen Smart Lock on September 9, 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.*