Update Java on a Windows 2008 R2 terminal server farm

#wip_java_update.ps1
#Java installer/updater
#Prerequisites PS 2.0 and http://archive.msdn.microsoft.com/PSTerminalServices. Only tested on 2008 R2.
#
#Setup - Change these to meet your needs
Import-Module PSTerminalServices
$Serverlist = new-pssession -computername ts01,ts02,ts03
$Message = "The server is going down for maintenance in 10 minutes. Please save your work and logoff."
$MailServer = smtp.mail.com
$MailSender = scripts@mail.com
$MailRecipient = admin@email.com
#
#Begin Install/Update
#Change logon mode to drain.
invoke-command -session $serverlist -scriptblock {change logon /drain}
#Send warning to all users
get-content x:\scripts\servers.txt | foreach {Get-TSSession -State Active -ComputerName $_ | Send- SMessage $Message}
#Wait X minutes
Start-Sleep -seconds 600
#Force all users to log off
get-content x:\scripts\servers.txt | foreach {{Get-TSSession -ComputerName $_ -Username [a-z]** | Stop-TSSession –Force}
#Copy installation application to temp folder on all servers
get-content x:\scripts\servers.txt | foreach {Copy-Item x:\jre.exe -Destination \\$_\c$\temp}
#change server mode to install
invoke-command -session $Serverlist -scriptblock {change user /install}
#Execute installer
invoke-command -session $Serverlist -scriptblock {c:\temp\jre.exe /s IEXPLORER=1 /L C:\setup.log}
#Wait X minutes. Need to add process query and resume when all installs are finished
Start-Sleep -seconds 360
#Change user mode to execute
invoke-command -session $serverlist -scriptblock {change user /execute}
#Change logon mode to enabled so that users can log back in
invoke-command -session $serverlist -scriptblock {change logon /enable}
#Set SMTP server
$smtp = New-Object Net.Mail.SmtpClient("$MailServer")
#Send completion email
$smtp.Send("$MailSender","$MailRecepient","Java Update Completed","Java installed!")
#Close all remote sessions created in this script
remove-pssession -session $Serverlist