A new stack, Celadon Cedar-14, is now available in beta.
In general, apps do not typically interact directly with this level of operating system services - but ultimately your app sits on a foundation provided by this stack image - a stack image we continuously patch and maintain.
This version of Cedar is built on Ubuntu 14.04 LTS. To learn the steps to migrate your app, read our Celadon Cedar-14 migration article. To learn about the differences between the two Cedar stacks, read Ubuntu packages on Cedar and Cedar-14.