Today, Jagex announced that both RuneScape Wiki and Old School RuneScape Wiki have moved from their old platform to a new home hosted by the game’s developer. According to the post, the wikis will still be run by the community and the Jagex staff won’t be interfering with them. So, other than the change in URL nothing else should be too different.
The announcement does state that it might support some other features in the future, such as multiple languages and… maybe… someday… in-game integration.
You can find the new links to both wikis in the official announcement on the RuneScape site.