Soon after the release of Crysis, a patch was announced as coming within two weeks. Those two weeks long since past, Crytek has finally sent out an update on the situation.
According to Crytek, good progress was being made until the company ran into "heavy technical issues" right before the final build. Though an updated version of the patch has been created, Crytek and EA quality assurance teams won't get to it before the first week of January. Crytek hopes that the patch will make it out soon after.
While that first patch only features performance updates and bug fixes, a second patch is being worked on simultaneously. This patch will incorporate fan feedback and introduce new single-player and multiplayer features. Once that patch has been released, the SDK will become available as well.