Problem with due date

Good afternoon everyone.Hope everyone is okay.
Although it is mentioned,asked and answered so many times in the forum i still havent found the sollution to my problem.I tried everything you mentioned in all the topics about the due date removal and nothing happens. I dont know whether the version of the programm matters but i am using Manager 18.1.88 desktop version.
Is there anything i can do to fix it or should i hire a programmer for example and write me a new code for sale invoices.
Thanks a lot in advance

You are about 1,000 versions behind. But that is not related to your question.

Manager requires due dates for sales and purchase invoices. If you do not assign one, Manager will, as explained in this Guide: Create sales invoices | Manager. If you want to suppress display of the due date on a completed invoice, that requires a custom theme. You will need to implement conditional logic in the portion of the theme that loops through the fields array. Most qualified web developers should be able to quickly write such a theme for you. Find someone with experience in the Liquid templating language. See https://www.manager.io/guides/10368.

thank you for both your time and answer .First i updated my program and yes i was left so so far behind. ok i will refer to an expert then. Thank again