diff --git a/Filesystem/File.vb b/Filesystem/File.vb
index 2f4365a6..814a3424 100644
--- a/Filesystem/File.vb
+++ b/Filesystem/File.vb
@@ -31,6 +31,76 @@ Public Class File
         _logger = LogConfig.GetLogger()
     End Sub
 
+    ''' <summary>
+    ''' Adds fileversions to given filename `Destination` if that file already exists.
+    ''' </summary>
+    ''' <param name="Destination"></param>
+    ''' <returns></returns>
+    Public Function GetVersionedFilename(Destination As String) As String
+        Try
+            Dim oFileName As String = Destination
+            Dim oFinalFileName = oFileName
+
+            Dim oDestinationDir = Path.GetDirectoryName(oFileName)
+            Dim oExtension = Path.GetExtension(oFileName)
+
+            Dim oVersionSeparator As Char = "~"c
+            Dim oFileVersion As Integer = Nothing
+
+            ' Split Filename without extension at version separator to:
+            ' - Check if file is already versioned
+            ' - Get the file version of an already versioned file
+            ' 
+            ' Example: 
+            ' test1.pdf         --> test1           --> ['test1']               --> no fileversion
+            ' test1~2.pdf       --> test1~2         --> ['test1', '2']          --> version 2
+            ' test1~12345~2.pdf --> test1~12345~2   --> ['test1', '12345', '2'] --> still version 2
+            Dim oFileNameWithoutExtension = Path.GetFileNameWithoutExtension(oFileName)
+            Dim oSplitFilename = oFileNameWithoutExtension.Split(oVersionSeparator).ToList()
+
+            ' if file is already versioned, extract file version
+            ' else just use the filename and set version to 1
+            If oSplitFilename.Count > 1 Then
+                Dim oVersion As Integer = 1
+                Try
+                    oVersion = Integer.Parse(oSplitFilename.Last())
+                Catch ex As Exception
+                    ' oFilenameWithoutExtension does NOT change
+                    oFileNameWithoutExtension = oFileNameWithoutExtension
+                Finally
+                    oFileVersion = oVersion
+                End Try
+            Else
+                oFileVersion = 1
+                oFileNameWithoutExtension = String.Join(String.Empty, oSplitFilename.Take(oSplitFilename.Count - 1))
+            End If
+
+            ' while file exists, increment version    
+            Do
+                oFinalFileName = Path.Combine(oDestinationDir, GetFilenameWithVersion(oFileNameWithoutExtension, oVersionSeparator, oFileVersion, oExtension))
+                _logger.Debug("Intermediate Filename is {0}", oFinalFileName)
+                _logger.Debug("File version: {0}", oFileVersion)
+                oFileVersion += 1
+            Loop While (IO.File.Exists(oFinalFileName))
+
+            _logger.Debug("Final Filename is {0}", oFinalFileName)
+
+            Return oFinalFileName
+        Catch ex As Exception
+            _logger.Warn("Filename {0} could not be versioned. Original filename will be returned!", Destination)
+            _logger.Error(ex)
+            Return Destination
+        End Try
+    End Function
+
+    Private Function GetFilenameWithVersion(FileNameWithoutExtension As String, VersionSeparator As Char, FileVersion As Integer, Extension As String) As String
+        If FileVersion <= 1 Then
+            Return $"{FileNameWithoutExtension}{Extension}"
+        Else
+            Return $"{FileNameWithoutExtension}{VersionSeparator}{FileVersion}{Extension}"
+        End If
+    End Function
+
     ''' <summary>
     ''' Removes files in a directory filtered by filename, extension and last write date
     ''' </summary>
diff --git a/Jobs/EDMI/ZUGFeRD/ImportZUGFeRDFiles.vb b/Jobs/EDMI/ZUGFeRD/ImportZUGFeRDFiles.vb
index 47feb79f..abdf4a63 100644
--- a/Jobs/EDMI/ZUGFeRD/ImportZUGFeRDFiles.vb
+++ b/Jobs/EDMI/ZUGFeRD/ImportZUGFeRDFiles.vb
@@ -6,6 +6,7 @@ Imports System.Reflection
 Imports System.Security.Cryptography
 Imports System.Text.RegularExpressions
 Imports System.Xml
+Imports DigitalData.Modules.Filesystem
 Imports DigitalData.Modules.Database
 Imports DigitalData.Modules.Interfaces
 Imports DigitalData.Modules.Interfaces.Exceptions
@@ -77,7 +78,7 @@ Public Class ImportZUGFeRDFiles
         Dim oAttachmentFile = MessageId & ".eml"
         Dim oAttachmentPath = Path.Combine(oAttachmentDirectory, oAttachmentFile)
 
-        If File.Exists(oAttachmentPath) Then
+        If IO.File.Exists(oAttachmentPath) Then
             Return oAttachmentPath
         Else
             Return String.Empty
@@ -97,27 +98,11 @@ Public Class ImportZUGFeRDFiles
         Dim oEmailData = GetEmailDataForMessageId(MessageId)
         Dim oSource = GetOriginalEmailPath(Args.OriginalEmailDirectory, MessageId)
         Dim oDestination = GetEmailPathWithSubjectAsName(Args.RejectedEmailDirectory, oEmailData.Subject)
-
-        Dim oVersion As Integer = 0
-        Dim oFileName As String = oDestination
-
-        Do While File.Exists(oFileName)
-            If oVersion > 29 Then
-                Throw New ApplicationException("Max. Move-Retries of 30 exceeded! Move will be aborted!")
-            End If
-
-            oVersion += 1
-
-            Dim oDestinationDir = Path.GetDirectoryName(oDestination)
-            Dim oExtension = Path.GetExtension(oFileName)
-            Dim oRootName = Path.GetFileNameWithoutExtension(oFileName)
-            Dim oNewName As String = oRootName & "~" & oVersion & oExtension
-            oFileName = Path.Combine(oDestinationDir, oNewName)
-        Loop
+        Dim oFinalFileName = _filesystem.GetVersionedFilename(oDestination)
 
         Try
-            File.Move(oSource, oFileName) 'oDestination)
-            oEmailData.Attachment = oFileName 'oDestination
+            IO.File.Move(oSource, oFinalFileName)
+            oEmailData.Attachment = oFinalFileName
         Catch ex As Exception
             _logger.Warn("File {0} could not be moved! Original Filename will be used!", oSource)
             _logger.Error(ex)
@@ -630,27 +615,12 @@ Public Class ImportZUGFeRDFiles
                     End If
                 End If
 
-                Dim oVersion As Integer = 0
-                Dim oFileName As String = Path.Combine(oFinalMoveDirectory, oFile.Name)
-
-                Do While File.Exists(oFileName)
-                    If oVersion > 29 Then
-                        Throw New ApplicationException("Max. Move-Retries of 30 exceeded! Move will be aborted!")
-                    End If
-
-                    oVersion += 1
-
-                    Dim oExtension = Path.GetExtension(oFileName)
-                    Dim oRootName = Path.GetFileNameWithoutExtension(oFile.Name)
-                    Dim oNewName As String = oRootName & "~" & oVersion & oExtension
-                    oFileName = Path.Combine(oFinalMoveDirectory, oNewName)
-                Loop
+                Dim oFileName = _filesystem.GetVersionedFilename(Path.Combine(oFinalMoveDirectory, oFile.Name))
 
                 _filesystem.MoveTo(oFile.FullName, oFileName, oFinalMoveDirectory)
 
                 _logger.Info("Finished processing file {0}", oFile.Name)
                 _logger.Info("File moved to {0}", oFileName)
-
             Catch ex As Exception
                 _logger.Warn("Could not move file {0}", oFile.FullName)
                 _logger.Error(ex)