SharePoint Online: How to Change List to New Experience?

• Go to List or Library settings >> Click on "Advanced Settings"
• Scroll down to the bottom, and from "List experience" section, Select "New experience" option and hit OK.

• Navigate to your SharePoint Admin Center(typically: https://YOURCOMPANY-admin.sharepoint.com/)
• Click on "Settings" from the Left navigation
• On the Setting page, under "SharePoint list and libraries experience" section, Select the appropriate option, such as : Classic experience or New experience (auto detect).

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
  
##Variables for Processing
$SiteUrl = "https://crescent.sharepoint.com/sites/sales"
$ListName= "Project Documents"
$UserName="salaudeen@crescent.com"
$Password ="Password goes here"
 
#Setup Credentials to connect
$Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($UserName,(ConvertTo-SecureString $Password -AsPlainText -Force))

Try { 
    #Set up the context
    $Context = New-Object Microsoft.SharePoint.Client.ClientContext($SiteUrl) 
    $Context.Credentials = $credentials

    #Get the document library
    $List = $Context.web.Lists.GetByTitle($ListName)
    #Set list properties
    $List.ListExperienceOptions = "NewExperience" #ClassicExperience or Auto
    $List.Update()

    $context.ExecuteQuery()

    Write-host "UI experience updated for the list!" -ForegroundColor Green        
}
catch {
    write-host "Error: $($_.Exception.Message)" -foregroundcolor Red
}

#Config Variables
$SiteURL = "https://crescenttech.sharepoint.com"
$ListName = "Team Documents"

#Connect to PNP Online
Connect-PnPOnline -Url $SiteURL -Credentials (Get-Credential)
 
#Set List Experience
Set-PnPList -Identity $ListName -ListExperience NewExperience

Get-PnPList -Identity "List Name" -Includes ListExperienceOptions

#Variable
$SiteURL ="https://crescent.sharepoint.com/sites/marketing"

#Connect to PnP Online
Connect-PnPOnline -URL $SiteURL -UseWebLogin

#Get the Root Web
$RootWeb = Get-PnPWeb
Write-host "Processing Root Web:"$RootWeb.URL -f Yellow

#Get All Lists from Root Web and Iterate through 
$Lists = Get-PnPList -Web $RootWeb
ForEach($List in $Lists)
{
    If($List.ListExperienceOptions -ne "NewExperience" -and ($List.Hidden -eq $false))
    {
        #Set List Experience to Modern
        Write-host "`tSetting List Experience to Modern:"$List.Title
        Set-PnPList -Identity $List -ListExperience NewExperience 
    }
}

#Get All Webs in the site collection and Iterate throgh
$Webs = Get-PnPSubWebs -Recurse
ForEach($Web in $Webs)
{ 
    Write-host "Processing Web:"$Web.URL -f Yellow
    
    #Get All Lists from web and Iterate through
    $Lists = Get-PnPList -Web $Web    
    ForEach($List in $Lists)
    {
        If($List.ListExperienceOptions -ne "NewExperience" -and ($List.Hidden -eq $false)) 
        {
            #Set List Experience to Modern
            Write-host "`tSetting List Experience to Modern:"$List.Title
            Set-PnPList -Identity $List -Web $Web -ListExperience NewExperience
        }
    }
}