Ok, thank you! Well, this reply is more correct and more useful. Not only to me, but to all others who would try to make something similar. Now we know that there is no guarantees that our self-made layout will work with next update. It is useful to know.
Little update:
All I had to do is to write in code instead in english “Due Date” - in serbian (which is my default language) “Rok”
Instead:
{% if field.label == ‘Due date’ %}{% if duedate == invoicedate %}{% continue %}{% endif %}{% endif %}
I Wrote:
{% if field.label == ‘Rok’ %}{% if rok == invoicedate %}{% continue %}{% endif %}{% endif %}
And everything works like a charm!