Over 25% of resources in Chrome are currently served over HTTP/2, compared to less than 5% over SPDY. Based on such strong adoption, starting on May 15th — the anniversary of theHTTP/2 RFC — Chrome will no longer support SPDY. Servers that do not support HTTP/2 by that time will serve Chrome requests over HTTP/1.1, providing the exact same features to users without the enhanced performance of HTTP/2.
If you haven't looked into HTTP/2 yet, it's time. A lot of best practices of HTTP/1.1 are no longer best practice in HTTP/2; for instance, HTTP/2 isn't so concerned about multiple requests for assets, so all those concatenated stylesheets aren't near the big deal they were. Zack Tollman and Aaron Jorbin gave a great talk at WCUS that goes into this, and other, technologies.