Release notice is here: https://getmonero.org/2018/10/11/monero-0.13.0-released.html

Also PLEASE be aware that you MUST be running some flavour of 0.13, either master, RC1, RC2, or release, in preparation for the upgrade on October 18th. More notes on the upcoming upgrade are in this thread: https://www.reddit.com/r/Monero/comments/9lcdme/preliminary_information_thread_regarding_the/

Riccardo