The Horizon Smartphone App allows you to make and receive calls using the Horizon IP telephony service from your iOS device. This is ideal for people who often work remotely or work from different locations where it is not practical to install a handset. In addition, the app also provides presence and instant messaging between users, keeping you connected to work colleagues no matter where you are.

Note: A Horizon account enabled for the iOS soft-client is required to use the app. Please contact your Horizon Service Provider for more information.

What’s New

Version 23.8.76

Bug fixes relating to Call History

Ratings and Reviews

3.0 out of 5
29 Ratings

29 Ratings

Russboy UK ,

Very buggy for a tech app

I’ve been using VOIP for years, at least 15 years now anyway and I had hoped by now that providers could supply interfaces allowing users to go about their daily business without throwing their phones at the wall every 5 minutes.

In some regards, this app works well...we have multi lines coming in, easily identified etc. But, there are bugs on iOS when you select a previous caller from the list ...sometimes it’ll call them, sometimes it’ll just hang. Other issues include selecting a contact from your iPhone contacts....the only option you have is to view the iPhone contact but it defaults to the first alphabetical contact on ones list meaning one has to manually type in a recipients number and ultimately add them to your horizon contacts.

Bit slapdash to be honest. My 14 year old nephew could whack up a more reliable interface.



Works as one would expect except the app developer has left off a function to turn off the app for times when you don’t want it ringing all the time like when you are sat in the office, on leave etc rather than having to sign out altogether.

They have removed the function to remember password which makes the above issue even worse as it’s a chore having to find the very long password and cut and paste it back in.

Still some work to do on this.

rokottyo ,

Lots of issues

Calls not coming through at all, or just going straight to voicemail, even though I haven’t put myself on do not disturb. Call quality is also poor, bad enough that clients complain about it. The fact that callers’ numbers show up on my phone’s private call history is also concerning, how does that fit with GDPR? Would not recommend this app or Gamma in general.


Gamma Telecom LTD
55.1 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad and iPod touch.



Age Rating


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

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