UpdateVersion.ps1

#Based on https://www.visualstudio.com/docs/build/scripts/index
# Enable -Verbose option
[CmdletBinding()] 

$VersionRegex = "\d+\.\d+\.\d+\.\d+"

$ManifestVersionRegex = " Version=""\d+\.\d+\.\d+\.\d+"""

if (-not $Env:BUILD_BUILDNUMBER)
{
    Write-Error ("BUILD_BUILDNUMBER environment variable is missing.")
    exit 1
}
Write-Verbose "BUILD_BUILDNUMBER: $Env:BUILD_BUILDNUMBER"

$ScriptPath = $null
try
{
    $ScriptPath = (Get-Variable MyInvocation).Value.MyCommand.Path
    $ScriptDir = Split-Path -Parent $ScriptPath
}
catch {}

if (!$ScriptPath)
{
    Write-Error "Current path not found!"
    exit 1
}

# Get and validate the version data
$VersionData = [regex]::matches($Env:BUILD_BUILDNUMBER,$VersionRegex)
switch($VersionData.Count)
{
   0        
      { 
         Write-Error "Could not find version number data in BUILD_BUILDNUMBER."
         exit 1
      }
   1 {}
   default 
      { 
         Write-Warning "Found more than instance of version data in BUILD_BUILDNUMBER." 
         Write-Warning "Will assume first instance is version."
      }
}
$NewVersion = $VersionData[0]
Write-Verbose "Version: $NewVersion"


$AssemblyVersion = $NewVersion
$ManifestVersion = " Version=""$NewVersion"""

Write-Host "Version: $AssemblyVersion"
Write-Host "Manifest: $ManifestVersion"
Write-Host "ScriptDir: " $ScriptDir

# Apply the version to the assembly property files
$assemblyInfoFiles = gci $ScriptDir -recurse -include "*Properties*","My Project" | 
    ?{ $_.PSIsContainer } | 
    foreach { gci -Path $_.FullName -Recurse -include AssemblyInfo.* }

if($assemblyInfoFiles)
{
    Write-Host "Will apply $AssemblyVersion to $($assemblyInfoFiles.count) Assembly Info Files."

    foreach ($file in $assemblyInfoFiles) {
        $filecontent = Get-Content($file)
        attrib $file -r
        $filecontent -replace $VersionRegex, $AssemblyVersion | Out-File $file utf8

        Write-Host "$file.FullName - version applied"
    }
}
else
{
    Write-Warning "No Assembly Info Files found."
}

# Try Manifests
$manifestFiles = gci .\ -recurse -include "Package.appxmanifest" 

if($manifestFiles)
{
    Write-Host "Will apply $ManifestVersion to $($manifestFiles.count) Manifests."

    foreach ($file in $manifestFiles) {
        $filecontent = Get-Content($file)
        attrib $file -r
        $filecontent -replace $ManifestVersionRegex, $ManifestVersion | Out-File $file utf8

        Write-Host "$file.FullName - version applied to Manifest"
    }
}
else
{
    Write-Warning "No Manifest files found."
}

Write-Host ("##vso[task.setvariable variable=AppxVersion;]$NewVersion") 

Would you have a script to change the app name according to branch name (so I can sideload the same app with different versions and settings)?