Dark Souls will switch from Microsoft’s Games for Windows Live to Steam a bit later than planned. The switch was planned for November, but now it looks to be on track for December. Namco revealed the delay on the game's Steam community page
where they wrote:“We are working hard to finalize the process to move your Dark Souls: Prepare to Die saves and achievements to Steam,” the update reads.
“We need to conduct additional testing and we are now targeting December to begin this process. We’ll have more information in the coming weeks. Thank you very much for your patience!”
Players will also be able to transfer their save data and achievements to Steam for a limited time.