Qt upstream in the dev branch is now going to Qt 6. I would like to start packaging for it in Lubuntu so we can port LXQt over as soon as it's reasonably possible. It's a multi-step process, and I'm assigning it to myself for reference, but help would be appreciated, especially when tracking upstream Qt 6 developments.

The timing should be right to have initial port in the archive for 20.10. This would make 20.04 the last Qt 5-based LTS, and just like our initial switch to LXQt, it would leave plenty of time for end user testing. I do fully expect the first release or two to have some rough edges, but that's par for the course. I would like to avoid another "Lubuntu Next" situation, especially since (from what I've heard) the port to Qt 6 will be fairly smooth.

Here are the steps for this:

• Create a PPA for Jenkins builds.
• Import the Qt packaging into Phab so we can quickly iterate on builds.
• Do the required refactoring in PPA Britney so an external PPA like this for a specific purpose can work.
• Ensure Qt always builds, track upstream changes, and get LXQt building using the latest Qt.
• Once the initial beta of Qt 6 is available, recheck the LXQt stack against Qt 6, and upstream our changes to Qt packaging and to LXQt.
• Work with the Debian Qt/KDE Team to get Qt 6 in both Debian and Ubuntu, and once it's available, upload Qt 6 ports directly to the archive.

It would be great if we could work to get this done before Plasma does, and be the first Ubuntu flavor to ship Qt 6 by default. We're far from getting Qt 5 completely off the ISO (that's probably 22.10 territory) but I'd like to be at the forefront of this.