On August 24th at 3:00 am PT for NA and 5:00 BST time for EUW servers will go down for maintenance and the 6.17 patch will be applied. EUNE is a bit of a different story this time around due to the upcoming server migration - they will receive the patch later on Thurs/Fri morning evening .
"On 08/24/16, starting at, 01:30 Pacific Time (08:30 UTC), ranked queues will be disabled in preparation for patch 6.17. At 03:00 Pacific time (10:00 UTC), the servers will be shut down and all games currently in progress will end in a draw and stats will not be recorded. We estimate the battlegrounds will be unavailable for 3 hours."Be sure to check your particular servers status page for your region's specific 6.17 maintenance times:
I'll keep you updated as more information on what the patch contains and patch notes become available. In the mean time, feel free to check the [ 6.17 PBE content ] for a tentative look at what is coming in the patch!