letter in product version

That is correct. That field only accepts values that conform to the .NET System.Version type, which does not accept letters. Also, I recommend using a local path for the Directory field, otherwise every target will always pass the Condition since you currently have it pointed at your file server.

I tried using a Collection, but it didn't work. It accepted the letter, but doesn't compare the version correctly.

Something you could try is using a PowerShell Scanner to convert the letter into a number. This example converts 8.7G into 8.7.7:

$Version = '8.7G'

# Grab the letter from the end of the version number and cast it to Char.
$VersionLetter = [Char]$Version[-1]

# Remove the letter from the version number.
$VersionWithoutLetter = $Version.TrimEnd($VersionLetter)

# Convert the letter into a number between 1 and 26.
# https://codegolf.stackexchange.com/a/90037
$LetterToNumber = [Int32]$VersionLetter - 64

# Append the number to the stripped version number and output the result.
"$VersionWithoutLetter.$LetterToNumber"

Thank you for the quick reply.
Can you trigger a "step" from the result of another "step" or simply call a "step" from a powershell script.

cordially.

I created this script with your help, it's work fine, but at the moment I still don't know how to update my packages automatically much like those in the library.

$excluded = @("*assistance*", "Desinstallation*", "Donnees*", "WD*")

get-childitem "C:\PROGRAM FILES (x86)\alcuin\*.exe" -exclude $excluded | foreach-object {
$softname = $_.Name
$softVer = [System.Diagnostics.FileVersionInfo]::GetVersionInfo($_).FileVersion
$nversion = $_.VersionInfo.ProductVersion
$VersionLetter = [Char]$nversion[-1]
$VersionWithoutLetter = $nversion.TrimEnd($VersionLetter)
$LetterToNumber = [Int32]$VersionLetter - 64
$NUMVersion = $VersionWithoutLetter+"-"+$LetterToNumber
#"{0}`t{1}`t{2}" -f $_.Name, [System.Diagnostics.FileVersionInfo]::GetVersionInfo($_).FileVersion, $NUMVersion
[PSCustomObject]@{
'Nom' = $softname
'version' = $softVer
'numversion' = $NUMVersion
}
}

I still don't know how to update my packages automatically much like those in the library.

This webcast may help with that: Automating Packages That Aren't in the Package Library