NSL7 Datastore version

I have just installed a new NSL 7 on an eDir system that has never
been in contact with NSL versions before.

From the top container where I have selected to place preferences and
apps, there is an Advanced option that says:
" SecureLogin SSO directory data version"

Here I can select 3.5 and 6.0. It defaults to 3.5.

Do I need to set this? Is it just displayed as 3.5 because it is the
first selection?
The manual seems quite vague on the matter.

Regards
Allan