The FIA has confirmed the introduction of a new generation of hybrid powered cars for the 2022 World Rally Championship.
In a raft of decisions coming from World Motor Sport Council meeting in Paris on Friday, the governing body has also raised the potential for the reintroduction of C segment World Rally cars, as well as a return to a control tyre for a three-year period from 2021 onwards.
The next homologation cycle for the WRC will include common electric motors and batteries for the first three seasons.
But the FIA has now introduced the potential for a second level of hybridisation to be introduced from 2025, which would allow for harvested energy to be used in competition and allow greater technical freedom for competing manufacturers.
The level of technological change - and the amount the teams will be permitted to do themselves - after the first three years will depend on the success of the first period of the hybrid rules.
An FIA statement explained that: "The cars will feature a supplementary hybrid system, to be comprised of common components and software for the first three years, with the potential for more technical freedom in 2025.
"The aim is to enable the cars to run on pure electric power in cities and provide an electric power boost on special stages."
On the subject of the size and shape of the new cars, the FIA statement read: "Manufacturers will be allowed to use a production bodyshell or a prototype tubular structure to current WRC size guidelines, while the FIA is set to define carry-over elements from production vehicles for key visual elements.
"There will also be an option for 'scaling' of the body within prescribed limits, to allow larger cars to comply with dimension targets."
The main field of the WRC will return to a control tyre formula for the first time since 2010, covering the 2021-2024 seasons.
Pirelli was the last single tyre supplier in the series - running from 2008-2010 - but since the start of '11, Michelin has won every round of the world championship except for DMACK's '17 Rally GB success with Elfyn Evans.
The FIA statement explained the move was "to reduce costs by preventing an escalation in tyre development". In other news announced by the WMSC, M-Sport will offer two WRC outings in a Ford Fiesta WRC in a new Junior WRC initiative sanctioned by the FIA.
The current Junior WRC structure will continue for the next two years, with the winner getting a Ford Fiesta R5 plus support package.
In addition, if that driver then wins the following year's WRC2 title, M-Sport will field a Fiesta WRC for them on two world championship rounds.
"To support this programme, M-Sport, in conjunction with Pirelli, has developed a national 'feeder' programme across Finland, the United Kingdom, Estonia and Italy that will allow them to step up into the world stage the following season," the FIA statement explained.
In regards to the 2020 WRC calendar, the schedule has been spiked and will be the subject of an electronic vote before the end of June.
The FIA statement read: "Approval of the 2020 FIA World Rally Championship calendar was deferred to the end of June 2019.
In the intervening period it will consider the potential rotation of competitions."
The FIA also confirmed a long-term extension to the current agreement with WRC Promoter.