The executive committee of Comiket 83 has announced on the official website that they will prohibit all the Kuroko no Basket-related circles from participating in Comiket 83 due to the threatening letter sent to the committee. The representatives of the committee said this was a regrettable decision but the police strongly requested not to allow KuroBas circles to attend the event. Distribution of KuroBas-related goods and dojinshi by other circles was also prohibited.
As a consequence of the series of threatening letter cases, many official and dojin events have been canceled including KuroBas live event at Jump Festa.
Source: Comiket 83 official website