Period of contracts on recurring invoice

Hello everybody,

I am new to Dolibarr (version 12.0.4) and am test driving it since ~ two weeks. Dolibarr nearly meets my requirements except one (as I hope) little thing.

I need to manage subscriptions, have created a contract and out of this an invoice template for recurring invoices. This works very fine as expected.

On the recurring invoice I need to print the period of the invoiced service which is ALWAYS from 1st of January to 31st of December (so I don’t have to deal with accruals). The problem now is how do I achieve the following getting printed on my automatically generated:
recurring invoice 1: “duration 01.01.2021 - 31.12.2021”
recurring invoice 2: “duration 01.01.2022 - 31.12.2022”
recurring invoice 3: “duration 01.01.2023 - 31.12.2023” and so on…

I could imaging to create 2 extra fields where I write the start and end date without the year, pull the year from the invoice date and put it into the generated invoice. But how?

Does anyone have the same problem and a solution or a great idea for that?

A big thanks to those who created and maintain Dolibarr. This is the best system I have ever seen.

Kind regards and thank you!