We just published ConstraintLayout 1.1.0 beta 6. This is the final RC before 1.1.0 stable. It’s available from the google maven repository:

dependencies {
    compile 'com.android.support.constraint:constraint-layout:1.1.0-beta6'
}

Documentation is available on https://developer.android.com/reference/android/support/constraint/ConstraintLayout.html

Changes:
  • Improved optimizer performances and exposed it (see documentation)
  • Additional experimental performance work with Chains (turned off by default)
  • Fixed several issues with margins support in Chains
  • Centering larger chains on smaller endpoints now works
  • Fix barrier issues (wrap_content behavior)
  • ConstraintSet issues with RTL fixed