{
    "orgName": "andrewfawcett Company",
    "edition": "Developer",
    "orgPreferences" : {
        "enabled": ["S1DesktopEnabled"]
    }
}

{
    "orgName": "andrewfawcett Company",
    "edition": "Developer",
    "settings": {
        "orgPreferenceSettings": {
            "s1DesktopEnabled": true
        }
    }
}

Replace Org preferences with scratch org settings
Replace Org preferences with scratch org settings

Org preferences are deprecated and have been replaced with scratch org
settings, as of Winter'20.
https://developer.salesforce.com/docs/atlas.en-us.sfdx_dev.meta/sfdx_dev/sfdx_dev_scratch_orgs_def_file_config_values.htm
