update xml nodes in powershell

I have an XML file that i need to update, however, when using this code

function SaveVersionNumber($Path, $Ver) {
[xml] $xml = Get-Content -Path $Path;
$info = $xml.versionInfos.versionInfo | where {$_.code -eq $Code}
$xml.Save($Path);   
Write-Host "Saving $Path with " (Get-FormattedVersion $Ver);}

function UpdateRevision($ver) {
#$ver.build = [string] ([int] $ver.build + 1);
[xml] $xdoc.versionInfos.versionInfo[0].build 
#return $ver;
return $xdoc;}

<?xml version="1.0" encoding="UTF-8">
<versionInfos>
   <VersionInfo code="sc">
     <major>1</major>
     <minor>1</minor>
     <build>1</build>
   </versionInfo>
<VersionInfo code="scw">
     <major>1</major>
     <minor>1</minor>
     <build>1</build>
   </versionInfo>
<versionInfos>

it doesnt update the values on any of the information.

This was previously working with code

and XML looked like this

function SaveVersionNumber($Path, $Ver) {
$xml.Save($Path);   
Write-Host "Saving $Path with " (Get-FormattedVersion $Ver);}

function UpdateRevision($ver) {
$ver.build = [string] ([int] $ver.build + 1);
return $ver;}

<?xml version="1.0" encoding="UTF-8">
   <VersionInfo>
     <major>1</major>
     <minor>1</minor>
     <build>1</build>
   </versionInfo>

any and all help very much appreciated