According to OpenSSL plans/schedule, version 1.1.0 will be released in May 2016. This release will break source compatibility:
Version 1.1.0 will (moderately) break source compatibility (for example we will make most structures opaque etc). Our current plans for the release timetable are:
14th April 2016, 1.1.0 beta 2 release
12th May 2016, 1.1.0 public release
A new SSL backend needed.