The present Technical Note outlines the new CMCC Seasonal Forecast System CMCC-SPS4 which will replace in operations, from August 1, 2025, the current system version CMCC-SPS3.5. The System is based on the new CMCC Ocean-Atmosphere Global Climate Model, developed and implemented at CMCC, the CMCC-CM3, which will be the basis for a large variety of activities, going from seasonal and decadal predictions to climate projections, in an almost seamless framework. The system performances are documented both in a “climate” perspective, that is running the system in climatological mode, with present-climate forcings and climatological initial conditions, and in seasonal forecast mode, with realistic initialization and temporal horizon of 6 months.