I've just released RAD RC13. I changed the internal UUID generator of RAD to use v8 UUIDs (using colossal-squuid library) instead of pure random ones, after a discussion with Cognitect about using unique UUIDs on entities in Datomic. They still strongly recommend SQUUIDs on databases that will get large. Of course, many other databases also have problems using random primary keys for things...so this should help prevent poorer than necessary db performance in the general case. (version RC10-12 were minor tweaks and releases on that path to 13).