# Letter Manager vs Universal Security Instruments

The clearest difference is in-app purchases: Universal Security Instruments at none against Letter Manager's 4. Universal Security Instruments also leads on rating (5.0 vs 4.6) and iOS requirement (14.0 vs 17.6). Letter Manager's advantage is ratings volume (19 vs 1) and update cadence (monthly vs every 2 months). On price, ads and device support there is nothing between them.

Both are free to download. Letter Manager sells 4 one-off in-app purchases. Universal Security Instruments asks for nothing beyond the download.

Universal Security Instruments holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Letter Manager has 19 ratings behind it against 1, so its average is the more settled of the two.

Letter Manager ships an update monthly, Universal Security Instruments every 2 months. The most recent releases landed on October 27, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | Letter Manager | Universal Security Instruments |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.6 (19 ratings)](https://appshunter.io/ios/app/letter-manager/id1514415524/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/universal-security-instruments/id6756246978/reviews)** |
| Number of ratings | **19** | 1 |
| Positive reviews | 86.4% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Monthly** | Every 2 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 31 MB | 200 MB |
| Requires iOS | 17.6 | **14.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Felix Reimann](https://appshunter.io/developer/1513019105) | [Feit Electric](https://appshunter.io/developer/1022520207) |

## What reviewers say

### Letter Manager

[App page](https://appshunter.io/ios/app/letter-manager/id1514415524)

Effortlessly write, format, and send letters with customizable templates. Scan and digitize incoming mail for easy organization and retrieval. Supports attachments and mail merges.

**Highlights:** Automatic DIN standard formatting, Save personalized letter templates, Attach PDF documents and images, Scan and digitize incoming letters, Keyword search for scanned text, Mail merge functionality, Export as PDF for email or print

**Features:** macOS Compatibility, Family Sharing, Vision Pro support, iPhone Duo support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Fullversion Birthday Edition | $2.99 | one-time |
| Fullversion with voucher | $3.99 | one-time |
| Fullversion | $5.99 | one-time |
| Fullversion for Dealers | $5.99 | one-time |


### Universal Security Instruments

[App page](https://appshunter.io/ios/app/universal-security-instruments/id6756246978)

Manage and control your smart security and environmental devices remotely. This app offers a central hub for all your connected products, allowing for easy setup, monitoring, and sharing of device access with others.

**Highlights:** Remote device management, Monitor devices globally, Share device access, Simple and secure setup, Centralized hub for USI products

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Letter Manager free?

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

### Is Universal Security Instruments free?

Universal Security Instruments is free to download, with no in-app purchases.

### Which has better reviews, Letter Manager or Universal Security Instruments?

Universal Security Instruments is rated higher. Letter Manager averages 4.6 out of 5 from 19 ratings, while Universal Security Instruments averages 5.0 from 1 ratings.

### Do Letter Manager or Universal Security Instruments have ads?

Neither Letter Manager nor Universal Security Instruments shows ads.

### Which is updated more often, Letter Manager or Universal Security Instruments?

Letter Manager ships an update monthly, and Universal Security Instruments every 2 months. Most recently, Letter Manager was updated on October 27, 2026 and Universal Security Instruments on October 16, 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.*