# Castel SIP vs SKYTEL UC

The clearest difference is update cadence: SKYTEL UC at every 2 months against Castel SIP's every 4 months. SKYTEL UC also leads on iOS requirement (12.0 vs 15.5). On price, ads, in-app purchases and monetization model there is nothing between them.

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

Castel SIP ships an update every 4 months, SKYTEL UC every 2 months. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Castel SIP | SKYTEL UC |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/skytel-uc/id1581528245/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | 60.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Free | Free |
| Size | 84 MB | 44 MB |
| Requires iOS | 15.5 | **12.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Castel](https://appshunter.io/developer/566301834) | [PortSIP Solutions, Inc.](https://appshunter.io/developer/426903821) |

## What reviewers say

### Castel SIP

[App page](https://appshunter.io/ios/app/castel-sip/id566301831)

This application functions as a SIP intercom softphone, enabling users to make and receive audio and video calls from IP intercom stations on their mobile devices. It allows for communication and remote door opening, working through Wi-Fi and cellular data networks.

**Highlights:** Audio and video calls, IP intercom station integration, Remote door opening, Address book with favorites, Call history, Remote commands during calls

**Features:** macOS Compatibility

**In-app purchases:** none


### SKYTEL UC

[App page](https://appshunter.io/ios/app/skytel-uc/id1581528245)

This app is a SIP-based softphone for iPhone, enabling Wi-Fi or cellular calls and instant messaging. It integrates with your contacts for easy management and supports advanced call features like merging and transfers. Enjoy secure communication with encryption and high-definition audio and video.

**Highlights:** SIP-based softphone, Wi-Fi or 4G/LTE calls, Instant messaging, Push notifications for calls/messages, Contact list integration, Call management (switch, merge, transfer), Video conferencing support, Secure call signaling and encryption

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Castel SIP free?

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

### Is SKYTEL UC free?

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

### Do Castel SIP or SKYTEL UC have ads?

Neither Castel SIP nor SKYTEL UC shows ads.

### Which is updated more often, Castel SIP or SKYTEL UC?

Castel SIP ships an update every 4 months, and SKYTEL UC every 2 months. Most recently, Castel SIP was updated on November 1, 2026 and SKYTEL UC on November 3, 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.*