Thanks for pointing that out! They appear to only support one of the two time models proposed by the research community. They support transaction time (when you write it), but not the interesting and useful 'valid time'. The difference can be explained as you are going to be paid a salary for working say from July 1, 2018 to June 30, 2019 (this is valid time), but we write the information into the db at a different time, say we write it on June 15 (this is transaction time), then we realize a mistake and update your salary record on June 20th. But your employment starts July 1.