Stable Build lines are actively developed for 10 months. This means there is a four month overlap between the creation of a new Stable Build line and the end of support for the previous one. You can choose when to upgrade to the new Stable Build line during the four month window. You can choose to stay on an older Stable Build line, but Azul does not make additional releases on those lines as often and does not release CPUs within the 48-hour SLA.
View the Azul Support Roadmap for more information about supported releases.