After nearly 40 years, the SRI will return to Hamburg where the first meeting was held in 1982. At that time DORIS was the only operating synchrotron source in Hamburg. The metropolitan area now hosts three unique research facilities: the European XFEL, PETRA III and FLASH at DESY. These three facilities complement each other and open up new research opportunities for scientists and industrial users of the international synchrotron radiation and free-electron laser community. Hamburg is once again ideally suited to be the venue of the next SRI conference. Rotating between Europe, America and the Asian-Pacific region, SRI conferences are hosted by countries with the most advanced light source facilities. They are organised by the international synchrotron radiation and free-electron laser community. The conference 2021 in Germany is expected to attract more than 1,000 participants.