Hello!
I have a joomla 2.5 website:
Joomla! 2.5.28, VirtueMart 2.6.6,
Template Information :Flexible Sportmart Version:1.0

I renewed the subscription and now I can upgrade it to joomla 3
I followed the general instruction about the upgrading (fix database, upgrade all the extensions including yours (have to mention that I couldn't update the t3 plugin, and Virtuemart) etc.. However, after the upgrade I get this error

Notice: Trying to get property of non-object in /var/www/vhosts/g....ore.com/httpdocs/shoes/plugins/system/flexibleTemplate/flexibleTemplate.php on line 20 Notice: Trying to get property of non-object in /var/www/vhosts/g....ore.com/httpdocs/shoes/plugins/system/flexibleTemplate/flexibleTemplate.php on line 20 Warning: require(/var/www/vhosts/g....ore.com/httpdocs/shoes/libraries/joomla/application/component/model.php): failed to open stream: No such file or directory in /var/www/vhosts/g....ore.com/httpdocs/shoes/administrator/components/com_virtuemart/helpers/vmmodel.php on line 24 Warning: require(/var/www/vhosts/g....ore.com/httpdocs/shoes/libraries/joomla/application/component/model.php): failed to open stream: No such file or directory in /var/www/vhosts/g....ore.com/httpdocs/shoes/administrator/components/com_virtuemart/helpers/vmmodel.php on line 24 Fatal error: require(): Failed opening required '/var/www/vhosts/g....ore.com/httpdocs/shoes/libraries/joomla/application/component/model.php' (include_path='.:/opt/plesk/php/5.3/share/pear') in /var/www/vhosts/g....ore.com/httpdocs/shoes/administrator/components/com_virtuemart/helpers/vmmodel.php on line 24

I know how complex the upgrade could be, so, is there any short step - by - step guide how to upgrade your Joomla Virtual Templates.
Thank you very much for your help!

Best regards,
Kostas

"Migration process” will be tough! that’s for sure.

Do you have the exact copy of this website on your localhost? You should definitely take care the migration on your localhost. Things are getting harder and slower on the live server.

1- Getting ready to Joomla 3.x

• Install your current website to localhost in 2 different places (i.e: http://localhost/newwebsite and http://localhost/oldwebsite — keep the oldwebsite handy, because you might need it as reference as you move along)
• Everything (plugins, components) should be compatible to Joomla 3.x ready before proceed. Otherwise you will end up with 500 - Internal Server Error.
• Via “Plugin Manager”, disable these plugins (because they are not compatible with J3.x)
• • Flexible VM2 Template
  • T3 Framework
  • plg_system_vm2_cart
  • System - jQuery Easy
• Update Virtuemart 2.x to Virtuemart 3.x
• Update Virtuemart AIO 2.x to Virtuemart AIO 3.x
• Update Joomla 2.x to Joomla 3.x (read this article for upgrading: docs.joomla.org/Joomla_2.5_to_3.x_Step_by_Step_Migration)
• Don’t attempt to open the Front-end yet, because most likely you will see the white-blank page (internal server error) in the front-end. The most important thing is not have any error in the Joomla Backend... for now.
• After upgrading to J3.x; if you end up with an white blank page (Internal Server Error) in the Joomla Backend, check the logs. It must be because of a plugin or components that is not compatible with J3.x. If this happens, you need to unpublished that plugin/components manually via PHPMyAdmin. After un-publishing it, find the j3.x version of it and re-install, then you can safely publish that plugin/components again via Joomla Backend.

2- Installing SportMart

• Install the SportMart using the "One-By One” installation method (not via QuickStart — because quickStart will retrieve everything back to stock)
• Via Template Manager, set the SportMart as your main template.
• Publish these plugins:
• • Flexible VM3 Template
  • T3 Framework
  • Flexible - Virtueamart Cart
  • System - jQuery Easy (ideally update this plugin for J3.x via extensions.joomla.org/extension/jquery-easy, then publish)
• You might need to modify the module position adjustments via Template Manager >> SportMart.
• If you did some custom modifications to Virtuemart Template override files, then you should re-do them.
• and you should be good to go, the rest is “adjustments” via Joomla Backend.

Tips & Advices

• The most critical thing is “not to get 500 Internal Server Error” during this migration in the Joomla Backend.
• After this migration; you will keep using your old modules, articles, menu-items, VM categories, and VM products. You won’t need to re-add them (which will save you lots of time).
• if you are okay with re-adding your contents, then you can abandon the migration process completely. Go head and install the SportMart via QuickStart installation method, then re-add your real contents basically by copy-paste from your old website. Depends on the number of Virtuemart products and Categories you currently have, this process will take some time, but this is the most stable and painless method.

Regards.
Support