SQL Server 2016 and 2017 system-versioned temporal tables are a very nice feature you can start using immediately, without changes to your applications. You can use them for auditing all changes in specific tables. You can retrieve the state of those tables at any point in time in history. You can find all states and changes in a specific period. SQL Server automatically updates the period in the current row and inserts the old version of the row into the history table as soon as you update the current row.
Nevertheless, there is still a lot to do in future versions of SQL Server. We still need better support for application validity times, including support for constraints and optimization of temporal queries, and more flexibility in the history retention policy.
In the next chapter, you will learn the basics of SQL Server security, together with new security features in SQL Server 2016 and 2017.