Sub ConvertDocToDocx()
'Updated by ExtendOffice 20181128
    Dim xDlg As FileDialog
    Dim xFolder As Variant
    Dim xFileName As String
    Application.ScreenUpdating = False
    Set xDlg = Application.FileDialog(msoFileDialogFolderPicker)
    If xDlg.Show <> -1 Then Exit Sub
    xFolder = xDlg.SelectedItems(1) + "\"
    xFileName = Dir(xFolder & "*.doc", vbNormal)
    While xFileName <> ""
        Documents.Open FileName:=xFolder & xFileName, _
            ConfirmConversions:=False, ReadOnly:=False, AddToRecentFiles:=False, _
            PasswordDocument:="", PasswordTemplate:="", Revert:=False, _
            WritePasswordDocument:="", WritePasswordTemplate:="", Format:= _
            wdOpenFormatAuto, XMLTransform:=""
        ActiveDocument.SaveAs xFolder & Replace(xFileName, "doc", "docx"), wdFormatDocumentDefault
        ActiveDocument.Close
        xFileName = Dir()
    Wend
    Application.ScreenUpdating = True
End Sub

Sub ConvertDocToDocx()
Dim oDlg As FileDialog
Dim sFolder As String
Dim sName As String, sFullName As String
Dim oDoc As Document
Dim i As Integer: i = 0
    Application.ScreenUpdating = False
    Set oDlg = Application.FileDialog(msoFileDialogFolderPicker)
    If oDlg.Show <> -1 Then Exit Sub
    sFolder = oDlg.SelectedItems(1) + "\"
    sName = Dir(sFolder & "*.doc", vbNormal)
    While sName <> ""
        If Right(LCase(sName), 3) = "doc" Then
            i = i + 1
            Set oDoc = Documents.Open(FileName:=sFolder & sName, _
                                      ConfirmConversions:=False, ReadOnly:=False, AddToRecentFiles:=False, _
                                      PasswordDocument:="", PasswordTemplate:="", Revert:=False, _
                                      WritePasswordDocument:="", WritePasswordTemplate:="", Format:= _
                                      wdOpenFormatAuto, XMLTransform:="")
            sFullName = Left(oDoc.FullName, InStrRev(oDoc.FullName, Chr(46)))
            If ActiveDocument.HasVBProject = True Then
                ActiveDocument.SaveAs sFullName & "docm", wdFormatXMLDocumentMacroEnabled
            Else
                ActiveDocument.SaveAs sFullName & "docx", wdFormatXMLDocument
            End If
            ActiveDocument.Close
        End If
        sName = Dir()
    Wend
    Application.ScreenUpdating = True
    If i = 1 Then
        MsgBox i & " document converted"
    Else
        MsgBox i & " documents converted"
    End If
    Set oDoc = Nothing
    Set oDlg = Nothing
End Sub