I have version 2 but its telling me that the available update is 1.5.8

You guys said that you have released a new update of version 2 but it is no where to be found!

Hello,

Booking 2 is still in beta version. There is already new release Booking 2.0.0-beta2.
You have to uninstall old version and install new manually. If you remove database tables before new installation, it would be ideal, because there are also some database changes.
If you have there important data, I think we can send you some script to upgrade your database.

Actual version is beta4. This version will allow you to install new version easily with online update.
Also older versions can be reinstalled, but you have to first uninstall Booking and then install beta4+. All missing tables and columns will be installed.

But for sure, create backup first.