An IISS blog comment on the apparent exit of President Nazarbayev announced a week ago, he has been in power since 1989, but it is clear his exit is heavily qualified:
The transition has been carefully coordinated to allow Nazarbayev to retain influence on the political system and to ensure that the interests of his family are protected. As prescribed in the constitution, a new interim president – Kassym-Jomart Tokayev, the former chairman of the senate and a trusted ally of the president – will serve out the remainder of Nazarbayev’s current term in office. In July last year, parliament gave Nazarbayev the right to head the national security council for life and upgraded the status of the body from consultative to constitutional. Nazarbayev remains the leader of the Nur Otan Party, which controls the legislature.
Link:https://www.iiss.org/blogs/analysis/2019/03/kazakhstan?

The BBC News story:https://www.bbc.co.uk/news/world-asia-47628854