Help! Problem with due date

Hello everyone
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.

To remove the due date you need a custom theme. Hire someone if you don’t have the skills.

And your version is about 1000 updates behind.