XF 2.1 SSO Available?

[Damien Alexander]

Is there a tutorial to have 1 same user account for 2 XenForo communities?

For example, I sign up as a new member on Site 1, and I can use the same login info on Site 2 and vice versa?

I know this was possible at one point because a site I was a member of did it

 

[Lukas W.]

There was an add-on around to achieve this in XenForo 1, but it's not possible out of the box.