In order to enter variables as invoice title in recurring invoices you need to:

1. Issue a proforma invoice (it will serve as a basis)

2. In Items Name enter variables, you may choose from: {{year}}   {{day}}   {{month}}  {{previous_month}}   {{next_month}} {{month_in_words}}  {{previous_month_in_words}}   {{next_month_in_words}}  {{month+1}} {{month+2}} {{month+3}} ... {{month+11}} {{month_in_words+1}} {{month_in_words+2}} ... {{month_in_words+11}}

3. Issue a New recurring invoice On the basis of the invoice. 

4. After generating a new recurring invoice, preview it and click edit. Check Issue VAT invoices if you wish to issue a standard recurring invoice based on the proforma.

5. If you wish to generate a recurring invoice instantly (to test variables) set the date to current in Next invoice date.

Example

In items' name you may enter:

Website maintenance for {{month}}.{{year}}

From now on every recurring invoice will look like this:

Website maintenance for 04.2014