The BANDAI NAMCO blog discusses their efforts at finding an alternative way to support multiplayer in Dark Souls besides Games for Windows LIVE, though they stress GFWL functionality will continue "for the foreseeable future." Here's word:

Dark Souls, Games for Windows Live, and the Future

With the release of Dark Souls II, many players have been asking questions about the continued support of Dark Souls I. We thoroughly appreciate the dedicated fans who are adventuring through Lordran (maybe for the first time!) and we’d like to clarify a few points:

1. Dark Souls will remain fully functional on GFWL for the foreseeable future.
2. BANDAI NAMCO Games is currently seeking avenues to continue support and ensure the functionality of Dark Souls on other services. We will have more news and updates to share on this in the coming months.

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