AzureADExtensionProperty.ps1

# Azure AD v2 PowerShell Module CmdLets for working with Extension Attribute Properties

# Connect to Azure AD with Global Administrator
Connect-AzureAD

# Get a User and Read Extension Properties
$aadUser = Get-AzureADUser -ObjectId <youruser>
$aadUser | Select -ExpandProperty ExtensionProperty

# Serialize User Object to JSON
$aadUser.ToJson()

# Explore Object Properties
$aadUser | Get-Member

# How to: Add Extension Properties
# PS! Can only write to Cloud homed users
$aadUser = Get-AzureADUser -ObjectId <yourclouduser>@elven.onmicrosoft.com
$extensionProp = New-Object "System.Collections.Generic.Dictionary``2[System.String,System.String]"
$extensionProp.Add('extension_<YourTenantSchemaExtensionAppId>_msDS_cloudExtensionAttribute1','ENTERPRISEPACK')
$extensionProp.Add('extension_<YourTenantSchemaExtensionAppId>_msDS_cloudExtensionAttribute2','EMSPREMIUM')
Set-AzureADUser -ObjectId $aadUser.ObjectId -ExtensionProperty $extensionProp

# Check added Extension Properties
Get-AzureADUser -ObjectId <yourclouduser>@elven.onmicrosoft.com | Select -ExpandProperty ExtensionProperty

#region List all users with Extension Properties
$aadUsers = Get-AzureADUser | Select DisplayName, ObjectId
$aadUsersExt = @()

ForEach ($aadUser in $aadUsers) {
    $user = Get-AzureADUser -ObjectId $aadUser.ObjectId | Select ObjectId, DisplayName
    $userDetail = Get-AzureADUser -ObjectId $aadUser.ObjectId | Select -ExpandProperty ExtensionProperty
        foreach ($key in $userDetail.Keys)
        { 
            if($key -like "extension_<YourTenantSchemaExtensionAppId>_msDS_cloudExtensionAttribute1")
            {
                $ext1 = $userDetail."$key"
            }
            elseif($key -like "extension_<YourTenantSchemaExtensionAppId>_msDS_cloudExtensionAttribute2")
            {
                $ext2 = $userDetail."$key"
            }
            else { $ext1 = ""; $ext2 = "" }
        }
    $obj = [pscustomobject]@{"DisplayName"=$user.DisplayName; "ObjectId"=$user.ObjectId; "Ext1"=$ext1; "Ext2"=$ext2}
    $aadUsersExt += $obj
    }

# List only users with values for extension attributes
$aadUsersExt | Where {$_.Ext1 -or $_.Ext2} | FT

#endregion

# List all users
$aadUsersExt

# Serialize users and extension attributes to JSON
$aadUsersExt | ConvertTo-Json