Upgrading Sapwood is a fairly manual process. The guides here help you jump from minor version to minor version smoothly.
To help regular the number of scenarios that need to be accounted for during the upgrade process, the process is only supported if you incrementally upgrade through each minor version. In other words, if you are on v1.1 and you are upgrading to v1.3, you must first upgrade to v1.2 and make sure everything is working smoothly.
As usual, if you encounter an error in the process, please create an issue.