Took them long enough! If you remember, back during the public test for patch 5.3, you could win some stuff just by playing on the test server. Play a single game and you got 5 of every single flag, and I think 10 or so wins got you a day of premium. Now those rewards are finally being rolled out, though right now EU and NA don’t seem to have a news post about it yet. If your account is on either of those servers, I imagine you might have to wait until you get the link from the news portal/launcher to claim your rewards.
According to the ASIA news, at least, you have until the 3rd of March to claim your public test rewards.