Does the Subject Identifier ("sub") in Sign In with LinkedIn using OpenID Connect ever change for the same member?

Hello,

Our app uses Sign In with LinkedIn using OpenID Connect. The userinfo endpoint (https://api.linkedin.com/v2/userinfo) returns a field called sub, which your documentation calls the "Subject Identifier."

We plan to store each member's Subject Identifier permanently, so we need to know exactly how it behaves. Please answer these questions:

1. Does the Subject Identifier stay the same every time the same member signs in to our app, forever? Or can it change for the same member?
2. Does it stay the same if the member changes their name, email address, or profile URL?
3. What happens if a member closes their LinkedIn account and later reopens it? Do they get the same Subject Identifier or a new one?
4. Is the Subject Identifier specific to our app (our client ID)? Would the same member get a different Subject Identifier in a different LinkedIn app? Your discovery document lists the subject type as "pairwise," and we want to confirm what that means for LinkedIn.
5. Does LinkedIn guarantee this behavior in writing? If so, please point us to the documentation.

Thank you,

Lou

******@gmail.com