A turbocharger system comprises a first relatively small high-pressure (HP) turbocharger and a second relatively large low pressure (LP) turbocharger. The turbine of the LP turbocharger is connected in series downstream of the turbine of the HP turbocharger. A first exhaust bypass flow passage provides a bypass flow path around the HP turbine. A second exhaust bypass flow passage provides a bypass flow path around the LP turbine. A rotary valve is located at a junction of the first and second bypass flow passages and a first exhaust gas flow passage. The rotary valve comprises a valve rotor which is rotatable selectively to permit or block flow to the LP turbine and to permit or block flow to the first and second bypass paths.