We just published ConstraintLayout beta 4. As always, it's available in the SDK Manager (under the "Support Repository" section).
Note: if you are using Android Studio 2.2, you might have to do File->Invalidate Caches & restart studio after installing this version (the editor behavior may not be correct, with widgets temporarily snapping to the top left corner or not shown).
This release fixes a few bugs related to guideline positioning and use of include tag, plus some additional performance improvement. We encourage you to update from previous versions.
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