I started working on a website 3 years ago. For the first year, I worked with a design company that created the original look for the website.
Since then, I stopped working with them and I changed the technology used for this website. Because of this change, I had to re-design the website (adding animations, new features, new views, etc.).
In the end, my design is based on the work done by this company during the first year, and then, by the work I have done and the enhancement I have done to this design for 2 years.
I want to acknowledge the work they have done but without saying "Designed by xxx". Is there a "standard" formulation that states that the design is based on their work that I iterated upon ?
I don't know if this is the right place to ask this (and the question can seem weird but I couldn't find a way to search for this question on internet) Thanks