You cannot rely on @@version (SELECT @@version) to identify which version of SQL Server engine is running your Azure SQL database as it will always show version 12 and it will continue to show version 12 indefinitely. That does not mean that Azure SQL is running as a SQL Server 2014 instance.
The version of the SQL Server database engine run by Azure SQL Database is always ahead of the on-premises version of SQL Server, and includes the latest security fixes. This means that the patch level is always on par with or ahead of the on-premises version of SQL Server, and that the latest features available in SQL Server are available in Azure SQL Database.
Please read my article about this topic.