I downloaded the latest fly app from the play store. It is not version 1.2.4., it is version 1.2.1 Should I download the 1.2.4 Version using my phone from DJI's site? It shows it as an APK download. What are your thoughts on this?

I would download it via the DJI website.  Having a conflict between firmware versions and app versions is a far greater risk than any potential Chinese spying on your flights.  

If you don't update from DJI's download page you'll be stuck with using v1.2.1 for the foreseeable future. Fly app v1.2.4 includes an in-app update notice and install feature, so you don't have to keep checking the  downloads page for a new version.

JohnLietzke Posted at 2-3 11:47
I would download it via the DJI website.  Having a conflict between firmware versions and app versions is a far greater risk than any potential Chinese spying on your flights.

All set, I downloaded it to my phone and google warned that it was a risk to install it. I allowed, or gave permission for the app to install, by trusting the site. Now when I fire up the app, go to settings, and look at the version, it is 1.2.4. Thanks

Meanwhile the app 1.2.4 will be provided at the Samsung Store.

JimDandy Posted at 2-3 14:37
All set, I downloaded it to my phone and google warned that it was a risk to install it. I allowed, or gave permission for the app to install, by trusting the site. Now when I fire up the app, go to settings, and look at the version, it is 1.2.4. Thanks

Not a problem.  I do not use an Android device with my drone.  But I did see on here a week or so ago that it was possible to update the DJI Fly app from settings menu with the version downloaded from the DJI website.
Yesterday, Niknik posted this video

From DJI, without hesitation.

WebParrot Posted at 2-4 14:23
From DJI, without hesitation.

Thank you. I have done the upgrade via dji’s site, to my Samsung galaxy A51. Went out and did a maiden flight. Shot 4K 25fps zoom. Beautiful. Only went out a few hundred feet, up 60 feet or so. It was very windy. All went great. I am typing this from my iPad Air 2, as I just updated my fly app to 1.2.4 through the dji site  for iOS . Looks like I’m all set. Now if autopilot would include the air 2 we’d be in heaven.

JimDandy Posted at 2-4 15:11
Thank you. I have done the upgrade via dji’s site, to my Samsung galaxy A51. Went out and did a maiden flight. Shot 4K 25fps zoom. Beautiful. Only went out a few hundred feet, up 60 feet or so. It was very windy. All went great. I am typing this from my iPad Air 2, as I just updated my fly app to 1.2.4 through the dji site  for iOS . Looks like I’m all set. Now if autopilot would include the air 2 we’d be in heaven.

You’re welcome.   I always hold high value when the updates come directly from developer (rather then thru a second or third source).

Hi, JimDandy. Thanks for reaching out! As already been suggested. you can download the APK file of the DJI Fly v1.2.4 from our Download Site. This DJI Fly version will have support for in-app updates to allow you to download and install the latest version of DJI Fly.