Update Email Addresses in SuccessFactors including the isPrimary Flag. Associated blogpost https://blog.darrenjrobinson.com/updating-and-setting-primary-attributes-in-successfactors-with-powershell/

Update SuccessFactors Email Address including isPrimary.ps1

$Global:headers = $null
$Global:SSFBaseURI = "https://api10preview.sapsf.com/odata/v2/"
$Global:SSFBusinessEmailType = "159139"  
$Global:SSFPersonalEmailType = "159140"  

Function Connect-SSF {
    [cmdletbinding()]
    param( 
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [string]$SSFBaseURI 
    )

    $creds = Get-Credential -Message "Provide the SuccessFactors loginID 'USER@Tenant' and Password for an account with SuccessFactors OData API access."
    
    if ($creds) {
        $Bytes = [System.Text.Encoding]::utf8.GetBytes("$($creds.UserName):$($creds.GetNetworkCredential().Password)")
        $EncodedAuth = [Convert]::ToBase64String($Bytes)
        [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12, [Net.SecurityProtocolType]::Tls11
        $Global:headers = @{Authorization = "Basic $($EncodedAuth)"; 'content-type' = 'application/json' }

        # Test Connection
        try {
            $ssfQuery = "$($SSFBaseURI)User?`$top=5"
            $ssfResult = $null 
            $ssfResult = Invoke-RestMethod -Uri $ssfQuery -Method Get -Headers $headers 
            if ($ssfResult.d.results.count -gt 0) {
                return Write-Host "Successfully connected to SuccessFactors."
            }
        }
        catch {
            Write-host $_
        }
    } 
}

Function Get-SSFUser {
    [cmdletbinding()]
    param( 
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [string]$employeeID,
        [string]$SSFBaseURI,
        [object]$headers
    )

    try {
        $ssfUserURI = "format=JSON`&`$orderby=personIdExternal asc`&`$expand=emailNav`&`$filter=startswith(personIdExternal,`'$($employeeID)`')"
        $ssfUserQuery = ($SSFBaseURI + "PerPerson?`$" + $ssfUserURI )
        $ssfResult = $null 
        $ssfResult = Invoke-RestMethod -Uri $ssfUserQuery -Method Get -Headers $headers 
        if ($ssfResult.d.results.count -gt 0) {
            return $ssfResult.d.results 
        }
        else {
            Write-Host "User Record with employeeID '$($employeeID)' not found."
        }
    }
    catch {
        Write-host $_
    }
}

Function Update-SSFEmail {
    [cmdletbinding()]
    param( 
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [string]$employeeID,
        [string]$SSFBaseURI,
        [string]$SSFBusinessEmailType,
        [string]$businessEmailAddress,
        [string]$SSFPersonalEmailType,
        [object]$headers,
        [Parameter(Mandatory = $false, ValueFromPipeline = $true)]
        [string]$personalEmailAddress
    )
    try {
        if ($personalEmailAddress) {
            $ssfEmailUpdate = "[{`"__metadata`": {`"uri`":`"$($SSFBaseURI)PerEmail`(personIdExternal='" + $employeeID + "'`,emailType='$SSFBusinessEmailType'`)`"},`"emailType`":`"" + $SSFBusinessEmailType + "`",`"emailAddress`":`"" + $businessEmailAddress + "`",`"isPrimary`":true},{`"__metadata`": {`"uri`":`"$($SSFBaseURI)/PerEmail`(personIdExternal='" + $employeeID + "'`,emailType='$SSFPersonalEmailType'`)`"},`"emailType`":`"" + $SSFPersonalEmailType + "`",`"emailAddress`":`"" + $personalEmailAddress + "`",`"isPrimary`":false}]"
            $ssfUpdateResult = Invoke-RestMethod -Uri "$($SSFBaseURI)upsert?`$format=JSON`&purgeType=Full" -Method Post -Headers $headers -Body $ssfEmailUpdate
        }
        else {
            $ssfEmailUpdate = "{`"__metadata`": {`"uri`":`"$($SSFBaseURI)PerEmail`(personIdExternal='" + $employeeID + "'`,emailType='$SSFBusinessEmailType'`)`"},`"emailType`":`"" + $SSFBusinessEmailType + "`",`"emailAddress`":`"" + $businessEmailAddress + "`",`"isPrimary`":true}"
            $ssfUpdateResult = Invoke-RestMethod -Uri "$($SSFBaseURI)upsert?`$format=JSON`&purgeType=Full" -Method Post -Headers $headers -Body $ssfEmailUpdate
        }
        return $ssfUpdateResult.d
    }
    catch {
        Write-host "SSF update failed" ($_.Exception.Response.GetResponseStream())
    }
}

Connect-SSF -SSFBaseURI $SSFBaseURI
$userDetails = Get-SSFUser -employeeID 10020618 -SSFBaseURI $SSFBaseURI -headers $headers

# New Business Address
$businessEmail = "darren@identirati.com"

# Get personal email address from result (if exist)
# Update SSF with Personal and Business email addresses and Business as the Primary
if ($null -ne ($userDetails.emailNav.results | Where-Object { $_.EmailType -eq $SSFPersonalEmailType })) {
    $personalEmail = ($userDetails.emailNav.results | Where-Object { $_.EmailType -eq $SSFPersonalEmailType }).emailAddress
    Update-SSFEmail -employeeID 10020618 -SSFBaseURI $SSFBaseURI -SSFBusinessEmailType $SSFBusinessEmailType -businessEmailAddress $businessEmail -SSFPersonalEmailType $SSFPersonalEmailType -personalEmailAddress $personalEmail -headers $headers
}
else {
    Update-SSFEmail -employeeID 10020618 -SSFBaseURI $SSFBaseURI -SSFBusinessEmailType $SSFBusinessEmailType -businessEmailAddress $businessEmail -headers $headers
}