Better session handling in OC 2.3

I understand that v2.3 is quite old and v3 already addresses this issue (at least you can work with db sessions). Nevertheless migrating to v3 is not a viable solution for me (too much custom code). So, I was wondering if there is a way to use db sessions in v2.3. I know some of the functionality is there but it's not complete, maybe someone has completed it and can share?

The problem I want to address: I need to place a limit for 1 connection per customer as there are problems with people signing in simultaneously from different devices/browsers (carts get messed up and using a one-page-checkout that conctantly updates the order is not helping).

P.S. This is not about the "wrong ip/mixed sessions" problem that occurs when behind a misconfigured proxy.

While the posted OC version decimal number is incomplete on the above, session libraries and startups have been re-handled in the master branch and on the maintenance branch already.