You can do it by doing:
UPDATE `invoices` SET `status` = 'void' WHERE `clients`.`client_id` = '1';
1 = Client ID.
To get Client ID go to their profile at the top you will see: /clients/view/742/ 742 is the client ID.
That's a feature request for more tags, but I believe you can do what you like using the current tags {invoices.______} the guys will be able to tell you. If you would like to know now, you can use {% debug %} and email yourself that template and you will get all the tags you can use.
x3 I take it is cPanel.
Go to cpanel, easyapache enable mbhash, mbstring, mailparse (if it's there). Then go to the pecl modules install mailparse and job done. However I've not used cPanel for a year and forgot most of it.
Are you looking for how to install PHP Mailparse?
cPanel: MailParse via Module Installers section on whm
Non cPanel: yum install php-mbstring php-pecl-mailparse php-mcrypt -y
What happens when you try the CLI? php /home/15/60/2016015/identivy-eu/web/index.php install
Looks like something to do with the remote mysql set-up like it's trying to use the buffering so I think it's something like this: http://stackoverflow.com/a/18985727 to fix it but I'm not a expert in this :s sorry.
Looks like you don't have PDO / PDO MySQL.
Do you own the server or use hosting?
If you own the server use non cPanel: yum install pdo pdo_mysql -y
If you own the server use cPanel: Re-compile EasyApache to have PDO, PDO MySQL.
Yes and Yes. Or on when making a payment click subscription and it will automatically pay invoices on Blesta as long as PayPal connects (should be automatic) but if not then you can use the IPN / API settings.