Hi, there has been some threads about the following Boost.Thread breaking change in release 1.53. "Breaking changes when BOOST_THREAD_VERSION==3 (Default value since Boost 1.53): There are some new features which share the same interface but with different behavior. These breaking features are provided by default when BOOST_THREAD_VERSION is 3, but the user can however choose the version 2 behavior by defining the corresponding macro. As for the deprecated features, these broken features will be only available until boost 1.55. * [@http://svn.boost.org/trac/boost/ticket/6229 #6229] Rename the unique_future to future following the c++11. * [@http://svn.boost.org/trac/boost/ticket/6266 #6266] Breaking change: thread destructor should call terminate if joinable. * [@http://svn.boost.org/trac/boost/ticket/6269 #6269] Breaking change: thread move assignment should call terminate if joinable. " I would like to request advise from the release managers and of course the Boost community. Should I rollback the default to BOOST_THREAD_VERSION==3 for 1.53 and let the time to discuss the best way to manage with these breaking changes? Best, Vicente