"Changes have been made to the flight program of the Russian Orbital Segment for increased efficiency. The launch of the Soyuz MS transport manned spacecraft, which had been scheduled for June 21, has been postponed to June 24," Roscosmos said in a press statement.
In March, Russia carried out its last ISS expedition launch using the Soyuz TMA-20M vehicle, which is the final model in the Soyuz TMA-M series of space vehicles. Future launches are set to be carried out on the Soyuz MS series.
The Soyuz MS-01 flight will carry Russia's Anatoli Ivanishin, Japanese astronaut Takuya Onishi and US astronaut Kathleen Rubins to the ISS.
The following ISS mission, Expedition 49, has been scheduled for September 23. Russia's Soyuz MS-02 spaceflight will take two Russian cosmonauts and one US astronaut to replace the current crew.