How do I create a company wide Excel function library?

I am used to creating generic functions and during these last few days I have
done so a lot, with help from you all.

I am wondering what is the appropriate way to store these functions and what
is neccesary to do or which parameter to set in the client PCs so that these
functions are available to everyone upon starting Excel. Bear in mind that I
have already a publicly accessible Templates folder where I store all company
templates.

What should be done when we change Office versions?

Thanks in advance