A new maintenance release of Polylang is available. It comes with two new translations: Serbian thanks to Sinisa and Myanmar thanks to Sithu Thwin.
It comes also with a new attempt to solve the “bad gateway” issue experienced by users hosted at wpengine.com. It took quite a lot of time, but thanks to the wpengine.com team which specially setup a free account for me to debug the issue, I believe I finally figured out what was wrong. At least another user reported that the issue was solved.