Jason Carter will not be attending JumpCon (Boston, Pittsburgh, or Washington DC).
Jason's name is still on the JumpCon website and tickets are still available for purchase, so because he is not attending do not purchase.
If you did purchase a ticket for Jason, per Shane's post on the JumpCon forums regarding refund/changes:
"Email sales@jumpcon.com or call 603-249-9002 for what you would like to change.