As they also continue work on Company of Heroes 2 under SEGA, the team at Relic Entertainment have announced and opened up a switch to Steamworks hosting for the original 2006 game and its expansions (thanks Strategy Informer
No explicit reason has been given for the change, only that "On May 7th the Company of Heroes’ online servers at server hosting company Quazal will be shut down". The multiplayer server and middleware tech company Quazal was acquired by Ubisoft in 2010.
A series of posts
on the developer's official forums detail the process players can take ot switch over to the new version ahead of the May 7th shutdown. Those that original purchased Company of Heroes via Steam should already be able to find a new entry for a "Company of Heroes (New Steam Version)" in their Steam Library, and those that purchased a boxed copy from elsewhere can redeem their CD keys via Steam's activation service.
Company of Heroes 2 is due on PC on June 25th 2013.