# Letter Tracking System vs Doomblock

The clearest difference is in-app purchases: Letter Tracking System at none against Doomblock's 2. Letter Tracking System also leads on iOS requirement (14.0 vs 17.0). Doomblock's advantage is update cadence (every 3 months vs every 11 months). On price, ads and device support there is nothing between them.

Both are free to download. Doomblock sells 2 in-app purchases, starting at $6.99 per month. Letter Tracking System asks for nothing beyond the download.

Letter Tracking System ships an update every 11 months, Doomblock every 3 months. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Letter Tracking System | Doomblock |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 11 months | **Every 3 months** |
| Size | 47 MB | 6 MB |
| Requires iOS | **14.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [GCCloud Info System Private Limited](https://appshunter.io/developer/1559340757) | [Lav Chaudhary](https://appshunter.io/developer/1896021221) |

## What reviewers say

### Letter Tracking System

[App page](https://appshunter.io/ios/app/letter-tracking-system/id6743742291)

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

**In-app purchases:** none


### Doomblock

[App page](https://appshunter.io/ios/app/doomblock-strict-app-blocker/id6790643079)

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Doomblock Pro Monthly | $6.99 | per month |
| Doomblock Pro Annual | $39.99 | per year |


## Frequently asked questions

### Is Letter Tracking System free?

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

### Is Doomblock free?

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

### Do Letter Tracking System or Doomblock have ads?

Neither Letter Tracking System nor Doomblock shows ads.

### Which is updated more often, Letter Tracking System or Doomblock?

Letter Tracking System ships an update every 11 months, and Doomblock every 3 months. Most recently, Letter Tracking System was updated on October 25, 2026 and Doomblock on October 24, 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.*