It looks like that rumoured mobile version of Final Fantasy 14 is on the way, as one has just been approved for release in China.
Last month it was reported that Tencent was working on a mobile version of the immensely popular MMO Final Fantasy 14, and it appears that said report has been confirmed. Niko Partners shared a report this week stating that China’s National Press and Publication Administration (NPPA) approved 15 import games on August 2, which includes some pretty big titles. As stated by Niko Partners, "A mobile game based on Final Fantasy XIV is being developed by Tencent and Square Enix and was approved." Obviously the language there suggests that it'll be its own game, rather than an outright port of the game.
Daniel Ahmad of Niko Partners shared on his personal Twitter account that this mobile take on Final Fantasy 14 is "expected to be a standalone MMORPG separate from the PC game," so it doesn't exactly sound like you'll be able to take your warrior of light with you in your pocket, at least not for the time being. When asked by someone on Twitter if the game is already done, Ahmad further explained that it "should be close to done" but "it could be another 3 to 6 months before we hear about it from Square Enix."