# DUO LINK 4 vs Feedstack

The clearest difference is in-app purchases: DUO LINK 4 at none against Feedstack's 3. DUO LINK 4 also leads on iOS requirement (11.0 vs 15.1). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Feedstack sells 3 in-app purchases, starting at $2.99 per month. DUO LINK 4 asks for nothing beyond the download.

DUO LINK 4 ships an update every 2 months, Feedstack every 6 weeks. The most recent releases landed on November 2, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | DUO LINK 4 | Feedstack |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.1 (513 ratings)](https://appshunter.io/ios/app/duo-link-4/id1103672387/reviews)** | — |
| Number of ratings | **513** | — |
| Positive reviews | 19.8% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 6 weeks** |
| Monetization | Free | — |
| Size | 123 MB | 43 MB |
| Requires iOS | **11.0** | 15.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [PNY](https://appshunter.io/developer/1103672386) | [Smira Shah](https://appshunter.io/developer/6787473482) |

## What reviewers say

### DUO LINK 4

[App page](https://appshunter.io/ios/app/duo-link-4/id1103672387)

Manage and transfer files between your iOS device and a USB flash drive. Free up storage, back up data, and even charge your device. Supports a wide range of file formats for seamless integration.

**Highlights:** Free up iPhone/iPad space, Charge iOS devices, Back up contacts, Transfer photos and videos, Store photos directly, Manage files, Music and video playback

**Features:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- 🚀 Efficient file transfer
- 💡 Useful for freeing up phone storage
- 👍 Straightforward to use

**What reviewers complain about**

- 🐛 Frequent app crashes
- 🔍 Confusing or limited UI
- 🔌 Compatibility issues with newer devices
- 💾 Data loss or corruption

**Reported bugs**

- App fails to detect connected device
- Transferred files not visible or accessible
- Inconsistent behavior when renaming folders

**Requested features**

- Add 'select all' option for photos/files
- Support for more file formats
- Improve iPad app experience
- Integrate with native Files app


### Feedstack

[App page](https://appshunter.io/ios/app/feedstack-habit-tracker/id6787473480)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| FeedStack Pro Monthly | $2.99 | per month |
| FeedStack Pro Annually | $17.99 | per year |
| FeedStack Lifetime | $24.99 | one-time |


## Frequently asked questions

### Is DUO LINK 4 free?

DUO LINK 4 is free to download, with no in-app purchases.

### Is Feedstack free?

Feedstack is free to download, with in-app purchases available.

### Do DUO LINK 4 or Feedstack have ads?

Neither DUO LINK 4 nor Feedstack shows ads.

### Which is updated more often, DUO LINK 4 or Feedstack?

DUO LINK 4 ships an update every 2 months, and Feedstack every 6 weeks. Most recently, DUO LINK 4 was updated on November 2, 2026 and Feedstack on October 28, 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.*