Hi I get the following errors when I am trying to update from 1.5.8 to 2.0.15 and using the VM Invoice upgrading feature

VM Invoice update: COM_VMINVOICE_ISVM1 not defined
File does not exist in upgrade package: //admin/tables/vmorder.php
File does not exist in upgrade package: //admin/tables/vmorderitem.php
File does not exist in upgrade package: //admin/tables/vmorderuserinfo.php
File does not exist in upgrade package: //admin/tables/vmuserinfo.php
File does not exist in upgrade package: /language/admin/sk-SK.com_vminvoice.ini
File does not exist in upgrade package: //site/assets/js/ajaxcontent.js
File does not exist in upgrade package: /language/site/sk-SK.com_vminvoice.ini
File does not exist in upgrade package: //site/assets/css/general.css
File does not exist in upgrade package: //site/assets/images/icon-16-edit.png
File does not exist in upgrade package: //site/assets/images/icon-24-refresh.png
File does not exist in upgrade package: //site/assets/images/icon-16-add.png
File does not exist in upgrade package: //admin/models/invoice.php
File does not exist in upgrade package: //admin/tcpdf/2dbarcodes.php
File does not exist in upgrade package: //admin/tcpdf/barcodes.php
File does not exist in upgrade package: //admin/tcpdf/datamatrix.php
File does not exist in upgrade package: //admin/tcpdf/encodings_maps.php
File does not exist in upgrade package: //admin/tcpdf/htmlcolors.php
File does not exist in upgrade package: //admin/tcpdf/pdf417.php
File does not exist in upgrade package: //admin/tcpdf/qrcode.php
File does not exist in upgrade package: //admin/tcpdf/spotcolors.php
File does not exist in upgrade package: //admin/tcpdf/tcpdf.php
File does not exist in upgrade package: //admin/tcpdf/tcpdf_filters.php
File does not exist in upgrade package: //admin/tcpdf/tcpdf_parser.php
File does not exist in upgrade package: //admin/tcpdf/unicode_data.php

What can I do, I have not tried to uninstall as I am afraid to loose existing config and invoices

Regards/Steve

Hello. That is because your current version is too old, there were some changes and our upgrade package doesn't already support that. Solution would be uninstall and install again, but in that former version database is deleted on uninstall.
So only solution for you would be perform upgrade manually - rewrite all files from package to your Joomla! folders.
But, there were also some database changes on mean time, so your database must be altered manually.
If you don't know how to do that, send me over your FTP and PHPMyAdmin credentials to Diese E-Mail-Adresse ist gegen Spambots geschützt! Du musst JavaScript aktivieren, damit Du sie sehen kannst. and I can do it for you. And sorry for these difficulties.