Yep, validated. Mirroring is still there in 2014.
You can see a listing of the deprecated features here. There are some that will be immediately removed in 2014 and there are others that will be removed "in a future version of SQL Server." Mirroring is safe through at least 2014.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning