# Cas vs Letter

The clearest difference is in-app purchases: Cas at none against Letter's 6. Cas also leads on device support (3 vs 1) and iOS requirement (14.0 vs 16.4). Letter's advantage is update cadence (every 5 days vs every 3 months). On price and ads there is nothing between them.

Both are free to download. Letter sells 6 one-off in-app purchases. Cas asks for nothing beyond the download.

Cas ships an update every 3 months, Letter every 5 days. The most recent releases landed on October 9, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | Cas | Letter |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 20.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 5 days** |
| Monetization | Free | — |
| Size | 47 MB | 70 MB |
| Requires iOS | **14.0** | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Stadt Castrop-Rauxel](https://appshunter.io/developer/1385393974) | [VUNYO](https://appshunter.io/developer/1768332147) |

## What reviewers say

### Cas

[App page](https://appshunter.io/ios/app/cas-app/id1261287227)

Access city information and services on the go. Report issues, find city contacts, and stay updated on local events and news. Manage waste collection and access utility information.

**Highlights:** News and events updates, Issue and idea reporting tool, City services directory, Waste collection schedules, Utility information access, Push notifications for alerts

**Features:** Vision Pro support

**In-app purchases:** none


### Letter

[App page](https://appshunter.io/ios/app/letter-write-send-post-mail/id6786452084)

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

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Credit | $1.99 | one-time |
| Credit | $4.99 | one-time |
| Credit | $6.99 | one-time |
| Credit | $9.99 | one-time |
| Credit | $19.99 | one-time |
| Credit | $49.99 | one-time |


## Frequently asked questions

### Is Cas free?

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

### Is Letter free?

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

### Do Cas or Letter have ads?

Neither Cas nor Letter shows ads.

### Which is updated more often, Cas or Letter?

Cas ships an update every 3 months, and Letter every 5 days. Most recently, Cas was updated on October 9, 2026 and Letter on September 28, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*