Magento have released a very encouraging and well received statement, at the start of Summer 2017. There is no Magento 1.9 End Date set.
The exec summary is that there are no plans to end support for Magento 1, and when they do intend to stop support they will provide 18 months notice.
Whilst Magento 2 uptake is gradually improving, we at Layer 5 are still actively developing and implementing new 1.9 systems for existing and new clients.
And now thanks to the Magento support statement issued we can be confident that existing 1.9 systems have a good lifespan ahead of them.
It’s our belief that the community ecosystem around Mag 1.9 wouldn’t leave anyone high-and-dry in the event of the end of official support, anyway; but it’s a clear signal from Magento to the module developer community to continue the upkeep of their own m1 modules for the forseeable.
Good news all round!