What potential issues can arise when switching from PHP 4 to PHP 5 in terms of vhosts?

When switching from PHP 4 to PHP 5, one potential issue that can arise in terms of vhosts is the need to update the PHP version specified in the vhost configuration files. This is necessary to ensure that the vhosts are using the correct PHP version. To solve this issue, you can update the "SetHandler" directive in the vhost configuration files to specify the appropriate PHP version (e.g., "proxy:fcgi://127.0.0.1:9000"). ```apache <VirtualHost *:80> ServerName example.com DocumentRoot /var/www/html <FilesMatch \.php$> SetHandler "proxy:fcgi://127.0.0.1:9000" </FilesMatch> </VirtualHost> ```