Generally, there is no specific dress code; some wear formal and some casual. Many adapt the semi-formal form to suit the mood of an international conference.
Monday Reception & Wednesday Banquet
A bit more formal format: i.e. Buffet with wine & live music show on a table.
Tuesday Evening Activity
If you join the Tuesday Evening Activity, casual clothing would be suitable with sneakers. It is expected walk a lot.
If you join the Friday tour, casual clothing would be suitable with sneakers.