[SM-G850F][Howto] Mirrorlink / Lollipop / Root

I have bought recently a Galaxy Alpha

Android : 4.4.4
Product code : SM-G850FHSEXEF
Version : G850FXXU2BNK3

I have rooted it with KingRoot
Why ? Because, I am living in France.
And in France, when you buy a product by web, you have 2 weeks during you can return the product if you are not satisfied with it.
And I doesn't want to use Odin due to the eFuse Knox

Nevertheless, I tried to connect by mirrorlink to my new car but it doesn't work.
I have installed Drivelink but no success

The galaxy alpha seems to be mirrorlink certified (soory, I can not post the link)

Due to the date of certification (April 2015) and these information in the following link (sorry I cannot put the link doclot.io/2015/04/29/6-mois-avec-le-samsung-galaxy-alpha/)

It seems that Mirrorlink work only with Lollipop

Do you know if , on Galaxy Alpha, mirrorlink works with KitKat or only lollipop ?

If it works only with Lollipop, I will have to update the android OS.
I have tried by OTA, but it doesn't work because It says that modification have been done
With Kies, It seems possible (I have not tried, I have just seen that a Lollipop update is proposed)

My question is root and lollipop.
How to keep root or to root after upgrade . Do I have to unroot before upgrade ?

Is Kingroot still working ? Or by Odin ?

I want to be root in order to delete somme applications I don't use

Thanks in advance for all your help.