I have to use QooApp too for Japanese games on my phone, too. To be honest I just prefer if Project Sekai had an English server, I think it'll more convenient altogether.When I first got my Samsung smart phone about 2 years ago, I wanted to download Japanese games but had problems because of locale and couldn't figure out how to easily make a Japanese region 2nd account compared to the small, easy steps for iPhone. I had to download QooApp to get Japanese games (basically a proxy sort of app that helps you download Japanese phone games). I am not a phone game person, so I don't know if it's easier to access apps or not nowadays. Hopefully someone can confirm.
The actual testing period has now been confirmed for May 15th 18:00 ~ May 16th 1:00Beta testing is set to begin on the 8th of this month