If you have configured selective First Release in your Office 365 tenant, you can easily get the list of First Release Users by means of the following PowerShell script:
https://gallery.technet.microsoft.com/How-to-get-First-Relase-db0ee3e0
############################################################################################################################################ # Script that allows to list of users to whom First Release has been configured in an Office 365 Tenant # Required Parameters: # -> $sUserName: User Name to connect to Office 365. # -> $sMessage: Message to show in the user credentials prompt. # -> $sOutputFile: CSV File with the First Release Users exported. ############################################################################################################################################ $host.Runspace.ThreadOptions = "ReuseThread" #Definition of the function that allows to export users configured in First Release function Get-FirstReleaseUsers { param ($sOutputFile) try { Write-Host "----------------------------------------------------------------------------" -Foregroundcolor Green Write-Host "Getting all First Relase Users in Office 365" -Foregroundcolor Green Write-Host "----------------------------------------------------------------------------" -Foregroundcolor Green $FirsReleaseUsers= Get-MsolUser | Where-Object { $_.ReleaseTrack -like "StagedRolloutOne"}|select Displayname,UserPrincipalName $FirsReleaseUsers $FirsReleaseUsers | Export-csv -Path $sOutputFile -NoTypeInformation } catch [System.Exception] { Write-Host -ForegroundColor Red $_.Exception.ToString() } } $sUserName = "<O365Admin>@<O465Domain>.onmicrosoft.com" #$sPassword = Read-Host -Prompt "Enter your password: " -AsSecureString $sPassword=ConvertTo-SecureString "<User_Password>" -asplaintext -force $msolcred = Get-Credential -UserName $sUserName -Message $sMessage Connect-MsolService -Credential $msolcred $ScriptDir = Split-Path -parent $MyInvocation.MyCommand.Path $sOutputFile = $ScriptDir+ "\PS_FirstRelaseUsers.csv" Get-FirstReleaseUsers -sOutputFile $sOutputFile
Referencia: