How to activate Hbook plugin

In the file hbook/utils/utils.php find the function verify_purchase_code which starts around line 28119 and add this to the start of the function code:

update_option( 'hb_purchase_code_error', '' ); 
update_option( 'hb_valid_purchase_code', 'yes' ); 
update_option( 'hb_purchase_code', $new_purchase_code ); 
return; 

Now you can use any key to activate the plugin and access all the options and menus etc.