mobile data always active on?

[Jonyny]

I don't remember exactly with Android 7.1.1 but after updating to Oreo, I noticed "mobile data always active" is on in developer option.

Then I found this article, 
http://www.androidpolice.com/2017/12/09/fyi-mobile-data-now-set-always-active-default-oreo/

Can anyone know if it's supposed to be on or off by default?

[Strampke]

On 7.1.1 it is switched off by default

[Jonyny]

Thank you Strampke,

How about after Oreo?

Mine is on, but what I'm not certain is if I turned it on with 7.1.1 by myself and that setting was passed on to Oreo, OR it was off with 7.1.1 and 8.0 turned it on.

[najodleglejszy]

1. it says "for some"

2. check the second to last paragraph in the article you linked to for possible side effects.