Hey lapji01. Welcome to the community.
You have posted this question to the Community Feedback space, which is a space for threads about this website and the forum functionality. You will want to post over in Discussions, where you will get more feedback about your question.
I've moved this to the Discussion area.
In v4 only one person could be in a database at a time.
This was not the case. I used v3, 4 and 5 extensively. What you describe sounds like a dangerous method of sharing the file amongst users via a shared volume instead of hosting the file with FileMaker Pro or FileMaker Server and then using Open Remote to access the hosted file. Using the correct and safe means of accessing the hosted file while hosted from FileMaker Pro would allow small number of users to access the files simultaneously while a much larger number can access using server.
This was true of FileMaker v4 as it is for FileMaker v15 today. The precise number of users allowed when hosting from Pro has varied, but it's never been the case of only one user at a time to a given file. Record Locking is much the same now as then as well.
Disconnect after Idle is a Server Feature.
We are using a virtual version of 4 on a company file sharing network and not allowed to host.
We will have 15 installed on all laptops but will still have to use the company file sharing server.
My question for idle disconnect is it for FM and just the program in general. I am by no means a FM expert and am completely self taught so sorry if my questions are basic.
Accessing any version of FileMaker via Filesharing is specifically warned against by FileMaker technical support. You risk damaging your files.
To have multiple users accessing the same file, it must be hosted--either on site, via a hosting service or FileMaker Cloud.