How To Upgrade To Miui 7.1.8 And Then Root It?

[pluver]

I already have a plan I just want to make sure.

I already have MIUI 7.0. The full device enscryption doesn't work.

So I want to upgrade to MIUI 7.1.8

There are so many ways to do so. Some says to use a prerooted rom, etc.

It seems that the simplest way is listed here:

http://en.miui.com/forum.php?mod=viewthread&tid=217175&highlight=Root+7.1.8&mobile=2

My current plan is

Use Xiaomi update app to install 7.1.8 ROM

It seems that I cannot wait for OTA updates to have an update. I got to download things.

If I update, is it okay? I mean now it's rooted. Is it okay to update a rooted ROM? Should I unroot first?

Then I expect to lost my ROOT access. Will I?

If so then I will follow instructions here

http://en.miui.com/forum.php?mod=viewthread&tid=217175&highlight=Root+7.1.8&mobile=2

Now, does the method there works for MIUI 7.1.8? Anyone confirm?

After that the OP talked about replacing KingRoot with SuperUser. Is Superuser an alternative way to root or is it something to replace after we root with KingRoot?

And why would anyone replace KingRoot with Superuser?

Why not have both, for example?

That's what's confusing to me.

All I want is

1. Full device enscryption that doesn't seem to work on MIUI 7.0.x
2. Stay rooted

Before I go ahead I just want to make sure