TempDB default number of files in SQL Server 2016
According to Paul Randal the number of tempdb files should be:


equal to the number of CPU cores for 8 or less cores
1/4 to 1/2 of CPU cores for more than 8 cores


I think it's a great news that Microsoft finally changed this default setting. The previous one was really bad - it caused problems with latch contention.

Paul Randal's article on the topic