Dreamforce is coming back to S.F. - with a 5,000-person capacity and mandatory vaccinations FacebookTwitterEmail Past Dreamforce conventions packed San Francisco’s Yerba Buena neighboorhood with lanyard wearing attendees. This year the conference’s capacity will be reduced and attendees will be required to be vaccinated.Jessica Christian/The Chronicle 2018 Dreamforce, San Francisco’s biggest convention, is returning to Moscone Center in September, but with significantly reduced capacity and a mandatory coronavirus vaccinations for attendees. Before the coronavirus pandemic, the tech conference sold out with 171,000 attendees and flooded the Yerba Buena neighborhood with lanyard-wearing crowds. But this year’s event, Sept. 21-23, is currently capped at 5,000 attendees because of public health restrictions on major gatherings. That could change if guidelines loosen.