Important Changes Since Chef 0.8
================================

  When upgrading from Chef 0.8.x to 0.9.x, be aware of a couple important changes.

    * 0.9 clients can read from 0.8 servers, but cannot save to 0.8 servers.
    * 0.8 clients cannot read or save from / to 0.9 servers.
    * The cookbook upload method is changed and cookbooks have to be
      uploaded to the server again.

  First, upgrade the server packages. Then upgrade the clients.

  Once the server is upgraded, cookbooks need to be uploaded again. Typically
  this is done from the Chef Repository (chef-repo) with knife. If the Chef
  Server is where the repository is located, simply:

      knife cookbook upload -a

  In the local chef-repo directory. If the repo is on another workstation,
  then upgrade Chef there and run the knife command, above.

  Two new configuration values are added to the server.rb:

    * sandbox_path
    * checksum_path

  Which are used for the new cookbook upload scheme.