We had an issue where the default number of versions in SharePoint was consuming a lot of space. We were able to reset the default, but there isn't a quick way to prune the old versions across and entire site (have to do it file by file) so built a quick and dirty PowerShell script we could use to handle one or more sites, limited to only PowerP…

prune.ps1

# Ensure you have installed PnP Powershell
# https://pnp.github.io/powershell/articles/installation.html

# Set Variables
$SiteURL = "https://{URL}.sharepoint.com/sites/"
# ragged array of two or three parameters:
# - the name of the site (to be concatenated with the $SiteURL), 
# - the root folder of the site to prune
# - optionally any message to display to the user while the script runs for that folder
$Sites = ("{site}","{root folder}"),("{site}","{root folder}","{comment to display}"),("{site}","root folder}")

$VersionsToKeep = 10

foreach($site in $sites)
{
    $url = $SiteURL+$site[0]+"/"
    #Connect to PnP Online
    Connect-PnPOnline -Url $url -Interactive

    Write-Host -f Green "Please wait, getting folder/file list for" $site[0]
    if ($site.Count -eq 3)
    {
        Write-Host -f Cyan $site[2]
    }
    $ListName = "/"+$site[1]

    $ListItems = Get-PnPFolderItem -FolderSiteRelativeUrl $ListName -ItemType File -Recursive

    Write-Host -f Green "Processing list for any documents with more than" $VersionsToKeep "versions"
 
    #Loop through each Item
    $cnt = 0
    foreach($File in $ListItems)
    {  
        $cnt += 1
        $i = [math]::ceiling($cnt * 100 / $ListItems.Count)
        Write-Progress -Activity "Processing Files" -Status "$i% Complete:" -PercentComplete $i
        if (($File.Name.Length -gt 6) -and 
                (($File.Name.Substring($File.Name.Length - 5) -eq ".pptx") -or ($File.Name.Substring($File.Name.Length - 5) -eq ".docx")))
        {
            $Versions = Get-PnPProperty -ClientObject $File -Property versions
            $VersionsCount = $Versions.Count

            $VersionsToDelete = $VersionsCount - $VersionsToKeep + 1
            If($VersionsToDelete -gt 0)
            {
                Write-Host "File:" $File.ServerRelativeUrl "[" $VersionsCount "]"
                Write-Host -f Cyan "`t Total Number of Versions to be deleted:" $VersionsToDelete
                #Delete versions
                For($i=0; $i -lt $VersionsToDelete; $i++)
                {
                    If ($Versions[$i].IsCurrentVersion)
                    {
                        $VersionsToDelete++
                        Continue
                    }
                    Write-Host -f Cyan "`t Deleting Version:" $Versions[$i].VersionLabel
                    Remove-PnPFileVersion -URL $File.ServerRelativeUrl -Identity $Versions[$i].ID -Force
                 }
                 Write-Host -f Green "`t Version History is cleaned for the File:" $File.Name
            }
        }
    }
    Write-Progress -Activity "Processing Files" -Completed
}

Disconnect-PnPOnline