For those of you using quark quickstart prior to the latest theme update, there are likely bugs you have had to fix - some that are fixed with the new vm update and some are not. As well, there are some new bugs - in particular with the order mail that many have complained about that will need fixing. If you prefer to wait and use your existing version with fixes in place and are using virtueplanet one page checkout, updating to the latest version without also updating to the latest version of virtuemart will break the state drop down in your OPC. Likely it is better for you NOT to update VP OPC, but if you did (like me) and have done too much additional work to go back to an earlier backup, here is the core hack to get vm to reshow the state drop down:
First of all, please remember if you can not update VirtueMart then you also should not update Joomla! above 3.5. Email problem starts only when you update to Joomla 3.5.1 without updating VirtueMart to 3.0.16 (or above). reCaptcha also wont work. PayPal payment plugin also may not work properly after their recent change in policy gets implemented. PHP 7 support is also not available in older versions of VirtueMart.
For both of your sites i.e. for VirtueMart 3.0.7.4 and 3.0.10, you can make the following changes to update the country/state field id.
Open - components/com_virtuemart/helpers/shopfunctionsf.php
Find the following codes around line 202 or 206:
return JHtml::_ ('select.genericlist', $countries_list, $idA, $attrs, $id, $name, $countryId);
Replace above by:
return JHtml::_ ('select.genericlist', $countries_list, $idA, $attrs, $id, $name, $countryId, $idA . '_field');
Now find the following codes around line 237 or 241:
$listHTML = '<select id="'.$_prefix.'virtuemart_state_id" ' . $attrString . '>
<option value="">' . vmText::_ ('COM_VIRTUEMART_LIST_EMPTY_OPTION') . '</option>
</select>';
Replace above by:
$listHTML = '<select id="'.$_prefix.'virtuemart_state_id_field" ' . $attrString . '>
<option value="">' . vmText::_ ('COM_VIRTUEMART_LIST_EMPTY_OPTION') . '</option>
</select>';
Save the file.
Now open - administrator/components/com_virtuemart/helpers/vmjsapi.php
Find the following codes around line 368 or 421:
$("#'.$prefix.'virtuemart_country_id").vm2front("list",{dest : "#'.$prefix.'virtuemart_state_id",ids : "'.$stateIds.'",prefiks : "'.$prefix.'"});
Replace above by:
$("#'.$prefix.'virtuemart_country_id_field").vm2front("list",{dest : "#'.$prefix.'virtuemart_state_id_field",ids : "'.$stateIds.'",prefiks : "'.$prefix.'"});
Save the file.
This should resolve the issue.
Please remember that the line numbers of the codes may change depending on your version of VirtueMart. You need to check and change the exact codes mentioned above.