InvoicePlane is a free software and it will never be a commercial product! We appeal everyone to respect the open source InvoicePlane project and our work and refrain from selling the application as their own product!
What you can do: offer paid professional support or hosting for InvoicePlane.

However InvoicePlane is an open source software released under MIT license. This means that you can use the code but the InvoicePlane name and the logo are copyright by Invoiceplane.com and Kovah.de
This means you have to use another name and logo for the product and include the original InvoicePlane license in the code.

For more information about licensing please visit the InvoicePlane website.

You have a problem with some errors, you are stuck and need help? We would like to help you but first we need some help from you: error logs.

1. Enable the debug mode by replacing ENABLE_DEBUG=false with ENABLE_DEBUG=true in the /ipconfig.php file.
2. Try again what caused the error, e.g. creating a new invoice which does not work.
3. Get the log files:
   • Open the folder /application/logs/, open the log file with the current date and copy the whole content.
   • Take a look at your web server error logs.
   • Open the console of your browser (tutorial), the error may be logged there.
4. Save the content of the log files and the output of the browser console to Paste.InvoicePlane.com and post this link with a detailed description to the Community Forums.
   You will get further help there.

Please make sure you copied the .htaccess file (hidden file on Unix systems) and you installed and enabled mod_rewrite for Apache.

If you want to install InvoicePlane in a sub-directory like yourdomain.com/invoices/ please follow the instructions for the installation in a subdirectory.

This problem occurs if the application is stuck because of an error. Please follow the instructions for the debug mode

This problem may occurs because of a configuration of your nginx webserver. The server error should look like this:

upstream sent too big header while reading response header from upstream

To solve this problem you should try to add / update your nginx configuration with the following settings:

proxy_buffer_size   128k;
proxy_buffers   4 256k;
proxy_busy_buffers_size   256k;

or

fastcgi_buffer_size 128k;
fastcgi_buffers 4 256k;
fastcgi_busy_buffers_size 256k;

Please check this comment for more details.

You can set the default invoice / quote groups at System settings > Invoices > Default Invoice Group for invoices and System settings > Quotes > Default Quote Group for quotes.

You can find all templates in the following directories:

/application/views/invoice_templates/

/application/views/quote_templates/

The templates are using basic HTML, CSS and PHP. If you just want to change the styling you just need some knowledge of HTML and CSS.
If you want to include Custom Fields into the templates please refer to the Custom Fields page.