The planning phase is done for each release which is every two months and according to the Release Calendars and is probably the most subjective task of ACS responsibilities. You have to take into account several factors:
- Ticket's impact and priority (Downtime, performance improvements, recovery times, etc.)
- Ticket's effort to implement
- Agreed/Scheduled deliverable (Java 11, Python 3, RTI DDS, etc.)
- Stakeholders requirements Requirements Gathering
- A meeting should be organized by Common with the goal of gathering
- There's a meeting organized by Control which tries to gather requirements from all subsystems interested in giving their input
- Resources available to a given period (Vacations, etc.)
Taking into account all these constraints a list of tickets and tasks are defined as the release deliverable products. , available in Release Notes after they've been scheduled.