Both RuneScape and Old School RuneScape are long-established MMORPGs with years of history behind each one, and soon players of both titles will get to relive that history all over again as Jagex has announced plans for fresh start worlds arriving to RuneScape on September 12th and OSRS in October.
An announcement post provides more information on how these servers will work in RuneScape, which will offer accelerated XP earnings and character boosts, along with rare halos to find, special halos for those who clear certain world firsts, and a progress point currency earned through gameplay that can be traded for various other rewards. These servers will be available for four months, after which characters can be transferred to a regular server.
As for the OSRS fresh start worlds, those will not have any sort of XP boosts on offer and will instead have its own unique economy and high scores to earn while still providing a familiar experience for fans of the MMORPG. These servers will run for six months and will also let characters transfer to the main game after that time.
More information about the RuneScape fresh start server can be read in both the announcement and in an FAQ.