Unfortunately Ubuntu for Android has been halted by now or at least until Canonical finds a suitable partner to bring it to phones. Maybe we'll finally see this becoming a reality with the 64bit smartphones on the horizon.
Direct quote from Canonical:
We still believe that U4A is a great product concept and that consumers would welcome the feature. The development within Ubuntu for U4A is complete. To take the development further requires a launch partner in order to make the necessary modifications on the Android side.
We are currently not in concrete discussions with launch partners, but we are still very much open to such a partnership. We are focused on Ubuntu for Phones at the moment, therefore we are not actively pushing for Ubuntu for Android.However, if a prospective partner steps forward, we are very much open to launching Ubuntu for Android.
Additionally, there has not been a release of a publically available (test-)version.