Get a Salesforce Preview Scratch org

Getting a Salesforce preview sandbox requires that you have a sandbox on a preview instance in time (see Salesforce Sandbox Preview Instructions) but getting a preview scratch org is easier I think as you can still do it. Just create a scratch org org and set the release key to preview in the config-file.

$ cat config/project-scratch-def.json 
{
  "orgName": "foo company",
  "edition": "Developer",
  "country": "US",
  "release": "preview",
  "features": ["EnableSetPasswordInApi"],
  "settings": {
    "lightningExperienceSettings": {
      "enableS1DesktopEnabled": true
    },
    "mobileSettings": {
      "enableS1EncryptedStoragePref2": false
    }
  }
}

$ sf create org scratch -f config/project-scratch-def.json --set-default