How Know the Right Version of Google Play Services For Your Phone?

The easiest way is to go to Settings > Apps > All Apps > Google Play Services which will bring you to this screen:

In this example we can see my current Google Play Services Version:16.0.89. Followed by (040408-...) Those 040408 numbers are the ones we want to find out the version for our phone. Obviously your phone can/will have different ones but refer to this as an example. 

Sometimes certain phones only show 448 (just like in the banner of this post) in that case you put a 0 before each number making it 040408. 

So let's pretend we want to download the version 12.6.85 for my phone. We can see there's many Variants on Apkmirror.com You just go on your browser and press CTRL + F and type the magic numbers 040408 in my case it found this result:

If it doesn't show up using CTRL + F then click on See More Uploads and browse until you find the version you are looking for.

Then proceed to download and install it accordingly.

Google Play Services (Download Link)