FX Turkey shared their Da Vinci's Demons season 3 trailer on You Tube, which indicates that they will be broadcasting Da Vinci's Demons 24 hours after Starz - which would make it October 25th. There are reports online of FOX Russia also airing on 25th October, but that hasn't been confirmed on their website. No other dates have been revealed yet.
The full press release from the TCAs last week has been shared on here, with more details about the Starz broadcast of the final season of Da Vinci's Demons. While the entire season will be available to watch on October 24th, Starz will continue to show weekly episodes, without a break on Saturday nights, with the final episode airing on December 26th. This doesn't really help any fans online around the world, who will sadly not be able to avoid massive spoilers. Such a shame the show doesn't get to build up to the final episode as fans want. Also, there appears to be an error about the broadcast time, as the premiere is going out at 8pm not 9pm as reported in the press release.