How to enable WiFi UMA Calling on the Leap?

I just bought an unlocked Leap while I was in the US and have an unlimited calling and data plan with T-Mobile.
However, I live in Japan and travel constantly. Making international calls is way too expensive so I always rely on UMA and WiFi calling in the past with all my previous Berries.

Can anyone help me enable the UMA and WiFi calling on my Leap?

I learned from Blackberry how to access the Engineering Screens already. It's actually pretty simple but, they are nothing like the old ones I'm used to and totally confusing.

This is the method they provided me:

How to access the engineering screen

Option 1 to access the Engineering screen:

1. Fire up your BlackBerry 10 browser and type in escreen:// in the URL field

2. This will fire up a dialog asking if you want to open the EScreen� Say yes

3. The browser will then minimize and invoke the EScreen app in landscape orientation

4. Go back to your browser or desktop browser and go to this link or this link to generate your EScreen unlock code. Just use the PIN, OS version, and uptime shown in the EScreen app. Select the number of days up to 30 that you wish the EScreen app to be unlocked for.

5. When you get the final code go back to your BlackBerry 10 device in the EScreen app and swipe up from the bottom bezel with two fingers to open the keyboard

6. Enter in the code you received from the generator and hit �go�
NOTE: you will not see any indication that your code is being accepted until you enter it in fully. Once it accepts the code it will open the full EScreen app. If the code does not work make sure you entered or generated it correctly and try again.

7. Proceed with EXTREME CAUTION!

Option 2 to access the Engineering Screen:

The new method uses URL schemes so, in order to get things started you'll need to open your web browser and visit: escreen:// and then tap go.

Once loaded, visit this page and enter in the info needed, which is displayed after visiting the above URL - Device PIN, OS Version, and uptime. Duration can be set to whatever you wish from the available options. If set to 30 days, you won't need to repeat the process for 30 days etc.

Once the info is entered, a code will be generated. From there, two-finger swipe up to raise the keyboard and then input the code as shown. No new screen or box will show for the input, just enter the code. No text input box will appear, so you're typing it blindly and it's not case sensitive. The escreen will then change, offering you access.

I hope the information above can help someone with more knowledge on the subject help me.

While the newer berries may be capable of Wifi Calling with TMO, they are not UMA capable anymore. UMA has been replaced by wifi calling. However, the phone must not only have TMO subscription, the phone itself must have an OS supported by TMO. I don't think the leap is one of the berries supported by TMO. The last phones to have TMO support and wifi calling were the Z10 and Q10 running 10.2.1.2228 if I am not mistaken. Later OS's don't have wifi calling support.

But just to satisfy your curiosity, go to BB world, search for the TMO wifi calling app and install it. There is no need to go the engineering screen. Although I have heard about engineering screen here at CB, that is not the way how i installed wifi calling. IF the options are greyed out, your phone is not supported. Also, if you are on a later build of BB10, later than 10.2.1.2228, your OS does not have wifi calling support.

You can't.

There are two requirements for TMO's WiFi calling to work:

1) A supported phone
2) An approved OS

Since you don't have 1, you don't have 2 either (TMO doesn't test or approve OSes for phones they don't support.)

Currently, the only phones that are WFC enabled on TMO are the Z10 (STL100-3 model) and the Q10 (SQN100-5 model.) The Classic (SQC100-4 model) is supposed to be getting it too, no later than next month.