SQL - simultaneous GC access ?

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I stumbled over comments in various threads that seem to refer to a future
implementation of SQL. Without all too much knowledge of the matter I
assume that means that GC is going to store it's data in an SQL (assuming
MySQL) database in the near future.

My questions in this regards:

1.) are my assumptions above correct?
2.) Will that also change the character of GC from being a single-user
system to a multi-user system?
3.) if 2.) is right, will there be a authorization routine for user's to
login?
4.) is there any plan to regulate access to certain parts of the accounting
to certain users? (for example a merchandiser being able to make supplier's
bills but not being able to access/see salaries)
5.) when will this SQL implementation go life?