Releases of the Operations Manual are orthogonal to Lustre releases and so the links above will always give you the latest and most up-to-date version of the manual, with clear indication on sections that only apply to certain releases.
The Operations Manual is developed much like the source code: anyone can submit patches, review changes and suggest improvements. Guidance on changing the Operations Manual is available here.
The manual workflow includes Gerrit and continuous integration practice. This enables changes to be automatically verified and conveniently reviewed using Gerrit.