The problem comes when we take in account UT-specific code, which makes usage of Qt private imports. I see, running 'grep' on my local folder where I keep all the UT code, that more than 10 components depend on them - including Unity8, the web browser, the Ubuntu UI Toolkit, the Ubuntu keyboard, and some Mir helper.

It means this software should be heavily tested in order to check if there's any regression. This is what Canonical used to do anytime they were moving to a newer version - IIRC they had to fix a few things when they moved to Xenial which uses Qt5.6.

A (partially) good news is that everything should have been already tested on Qt 5.6 and it should just work "out-of-the-box". Anyway I don't think there's any value in moving from the current patched version of Qt 5.4.x to another - as long as we stay on vivid, Qt 5.4 is not the problem.

I think this should be one of the main discussions after we've started to work on Xenial. Qt version, UITK, Unity8, Mir, and the package format are things extremely related each other. The only thing that I can say for sure is that it wouldn't be a problem if we were on Snaps, Flatpaks or Appimages, since they bundle a specific version of the required libraries...

BR

The version: "0.7."
I guess that last dot is giving some trouble to the system, which can't properly register the application. This is something we need to fix after we've moved the core apps from launchpad.net to GitHub, since we can't invoke "bzr revno" anymore.
Usually other core apps specifies a fallback string in case "bzr" is not available. I see such fallback is missing in terminal-app.

Look for the following piece of code in ./CMakeLists.txt (should be at line 46)

if(NOT BZR_REVNO)
  execute_process(
    COMMAND bzr revno
    OUTPUT_VARIABLE BZR_REVNO
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    OUTPUT_STRIP_TRAILING_WHITESPACE
  )
endif(NOT BZR_REVNO)

And add the following:

if(NOT BZR_REVNO)
  set(BZR_REVNO "latest")
endif(NOT BZR_REVNO)

After this change (and having disabled tests for convenience), I've been able to launch the app on my BQ.

QML imports
There's another problem that clearly Canonical engineers forgot to fix. They forgot the phones.
The source code has been updated to use QtQuick 2.5 imports, which require Qt 5.5 to be installed on the system. Sadly, Ubuntu Touch is still on Qt 5.4, therefore the application can be launched, but it get stuck on the loading screen.

We need to check if QtQuick 2.5 is really necessary and, in case, downgrade to Qt5.4. I don't exclude further issues anyway.

Forget what I said anyway, now I recall that after I leaved the terminal-app team, it received some contribution in order to converge to desktop platform. There might be a problem in the source code, let me check...

Have you tried to trigger a "pull down to refresh" gesture in the application scope, in order to refresh the scope content? When you install apps from terminal, the scope doesn't get automatically refreshed.
Otherwise, I'd suggest you to install "UT Tweak Tool" from the OpenStore, which performs all the steps automatically.

But then I coudn't find the app in the app scope, and using the methods described in my previous message I could not start the app either.

i.e. If you use the Ubuntu SDK green "play" button on the sidebar, that's just meant to build and run your application for debugging/development reasons. Once you close the application on your device, the built package is uninstalled. You should use the actions in the "Publish" tab instead, if that's the case.

I tried launching it using "phablet-shell" with:
ubuntu-app-launch com.ubuntu.terminal_0.7.
but no matter how I write the name of the app I get:
** (process:12079): WARNING **: Unable to start app 'com.ubuntu.terminal_0.7.': AppID is empty
I've also tried with other combinations from the name of the click package:
com.ubuntu.terminal_0.7._armhf.click
like "com.ubuntu.terminal_0.7._armhf" or just "com.ubuntu.terminal" and similar, but always the same message. I also tried with "terminal-app" but same message.

Then I checked in .local/share/applications and there I could find a desktop file and this line to launch the app:
Exec=aa-exec-click -p com.ubuntu.terminal_terminal_0.7. -- lib/arm-linux-gnueabi
hf/bin/terminal
I tried then:
aa-exec-click -p com.ubuntu.terminal_terminal_0.7. -- lib/arm-linux-gnueabi
hf/bin/terminal
and get:
aa-exec: ERROR: profile 'com.ubuntu.terminal_0.7.' does not exist
I also tried without the last option as I don't have the directory:
aa-exec-click -p com.ubuntu.terminal_terminal_0.7.
same message.

Any tip to debug this, very welcome.

GM

About core apps: I agree, there's a lot to be improved yet, and my rational thinking says that we should focus only on a small set of core apps, on a specific type of device (i.e. phone) and forget the rest.
What we'd need then is to provide the best development framework we could offer, in order to allow third parties to support those services with the minor effort.

I'm going a bit OT, but you can understand how I think that we should stop talking about convergence and focus on having something that really works first.

The biggest chance for me to switch to UT has been the BQ M10, as a replacement for my old netbook. I want convergence, but it needs to be something that really works, with no hackish stuff.
IMHO, if the BQ M10 was shipped with Ubuntu GNOME (and GNOME Shell), that would have been the best buy for everyone. UT was pretty far from offering such user experience.

This is something that should be considered for future development.

BR