Remaining still in the early phase of development Soyuz-5 rocket seems to be universal solution for at least two problems for Russian space industry: upcoming retirement of Proton and lack of rocket which could be launched from Sea Launch see platform.
According to official statement RCC Energia was selected as primary contractor for Soyuz-5 carrier rocket. Company will develop rocket in the cooperation with Roscosmos State Corporation with support of other subcontractors like Progress Rocket and Space Center and the Center for Operation of Ground-based Space Infrastructure Facilities.
According to official statements Soyuz-5 should perform its first flight in 2022 and deliver to orbit new "Federation" manned spacecraft in 2024.
Soyuz-5 will be medium carrier rocket able to operate from both conventional launch sites at Baikonur, Kazakhstan and special sea platform operated by Sea Launch company. Rocket is developed under Phoenix program which had secured $498 million for years 2018-2025.
Rocket is planned as two stage vehicle with first stage powered by RD-171MV and second stage second stage by the RD-0124M engine. Rocket will be long for 46.5 m with diameter of 3.6 m. Mass of the rocket is planned for 270 t with payload to LEO orbit of 9 t.