From the iGEM website:
With 340 teams this year, the iGEM Competition is bigger than ever! Due to the growing interest, we are excited to announce that the 2018 Giant Jamboree will be returned to our regular 4-Day program to accommodate so many amazing teams. Thursday, October 25 will now begin with the Opening Ceremony, followed by team presentations and posters. Just as in previous years, this schedule will have three full days of presentations, poster sessions, and workshops, so that everyone can make the most of their Jamboree experience.