SQL Server 2017

I attend the 2018 PASS conference in Seattle.
In several of the sessions, Microsoft stated that SQL Server 2017 will support older issues
of SQL Server by setting the Compatibility Level of the database to the older versions.
That works fine.

The issue for me now is backups, I can not create a backup in SQL Server 2017 that I can restore
to older versions of SQL Server Engine. To make this happen, I have to find a computer with the older
version of SQL Server. Then create scripts to create the database and move the data in the older version of SQL Server and then do a backup there. Is this the only way to accomplish this?

This comes into play with Third Party Applications that I support who do not have the higher version of SQL Server.

you tried this ^^ and what happens?

You can script the objects (logins, users, table, SPs, views etc) then bcp the data out and in to the destination (similar to what you do with a corrupt database).
You might have to make changes (maybe with the extract) as there may be features and structures that are not supported by the older version.
You will probably find that the code needs to be altered to remove errors and it also may act differently so needs to be tested.

If you need to make your system compatible with older versions you should consider developing with the oldest applicable then migrating forward for testing and distribution or you'll find you use features that are difficult to replicate.