Those earlier launches were as a two-stage sounding rocket. The three-stage variant capable of putting a payload in orbit first launched in 2017; it made orbit

Those earlier launches were as a two-stage sounding rocket. The three-stage variant capable of putting a payload in orbit first launched in 2017; it made orbit on its second flight earlier this year. SS-520 is a one-off experimental project, not something they intend to put into regular commercial service.