In Crysis Monthly Update #1 Crytek confirmed that there won't be any more updates to Crysis that "there almost certainly will not be a patch 1.3" for the shooter. The reason for the decision, that company informs in its first monthly update on the game, will be revealed "in the very, very near future".
At this time, there almost certainly will not be a
patch 1.3 delivered for Crysis. We are aware that this news will
disappoint many of you, and we would like to apologize profusely. There
is a good reason for this and we hope you understand when you hear more
about the reasons why in the very, very near future. Please realize
this was an extremely difficult decision, but please do know that we
are listening to your comments and are making more consistent community
support a high priority. We are confident that the things we are
working on will be appreciated by the community, and we hope for your
continued support. If you have any questions or concerns please feel
free to contact us.
It's worth remembering that Crytek trademarked Crysis: Warhead back in March. No additional information is available at this time. However, it could be an add-on...(?)