Hi!
There are two fields changed in "f" version:
***** install_org.sql
`product_currency` smallint(1),
`product_price_publish_up` datetime,
`product_price_publish_down` datetime,
`price_quantity_start` int(11) unsigned,
***** INSTALL.SQL
`product_currency` smallint(1),
`product_price_vdate` datetime,
`product_price_edate` datetime,
`price_quantity_start` int(11) unsigned,
*****
And they are used in .../models/product
if($front){
if(count($virtuemart_shoppergroup_ids)>0){
$q .= ' AND (';
foreach($virtuemart_shoppergroup_ids as $sgrpId){
$q .= ' `virtuemart_shoppergroup_id` ="'.$sgrpId.'" AND ';
}
$q = substr($q,0,-4);
$q .= ' OR `virtuemart_shoppergroup_id` IS NULL OR `virtuemart_shoppergroup_id`="0") ';
}
$q .= ' AND ( (`product_price_publish_up` IS NULL OR `product_price_publish_up` = "' . $db->getEscaped($this->_nullDate) . '" OR `product_price_publish_up` <= "' .$db->getEscaped($this->_now) . '" )
AND (`product_price_publish_down` IS NULL OR `product_price_publish_down` = "' .$db->getEscaped($this->_nullDate) . '" OR product_price_publish_down >= "' . $db->getEscaped($this->_now) . '" ) )';
}
Hope it helps

Best Regards
Cezar