1. Purpose and scope
Sustaining is shared on a platform: a fix or security update in the platform has to reach every product built on it. That is the platform's greatest strength after release, because one fix serves many products, and its greatest burden, because every change must be checked against configurations the platform team may never have built itself, and because old platform versions must be kept alive for products still in the field.
The stage has two rhythms. The maintenance rhythm delivers platform maintenance releases: fixes, security updates, IP maintenance releases, firmware and software maintenance releases and toolchain updates, each validated on the supported derivatives and released with notes and advisories. The review rhythm holds platform roadmap reviews, where use, cost, support load and technical debt are weighed against plan and the team decides whether to extend the platform, start its next version or plan its retirement.
In scope: platform change control after release, maintenance releases across IP, firmware, software and tools, the platform maintenance baseline, vulnerability response and security advisories across derivatives, IP version and errata notices, derivative usage and feedback, support and usage metrics, and roadmap reviews. Out of scope: new derivatives, which go through Derivative Product Development, and the platform's closure, which belongs to Platform Retirement.
12 more sections for registered members.