This DEC Plan for CAELESTIS aims to serve as an information and control instrument for all dissemination, exploitation, and communication (DEC) activities among all partners in the project. For the first project Reporting Period (RP1; M1 – M18), activities, messaging, SOPs, and stakeholders were all defined in the Initial DEC Plan (D8.1). As stipulated in D8.1, throughout the lifetime of the CAELESTIS project, the DEC plan must be periodically updated and adapted based upon various inputs, including those stemming from the innovation management findings in WP9; stakeholder analysis; refining key messages to various target groups; social media analytics. This document is the first such update to the CAELESTIS DEC Plan.