How the old version looks like
How the new version looks like
A bit of context
The Double Diamond is a process created by the British Design Council in between 2004 and 2005. It's form has served as an inspiration for many other Design processes. In 2019 an update of the process was published fixing a few issues of how the Double Diamond was understood and used by the community.
What I like about it
The first thing that I find extremely interesting in this process is the separation of modes of thinking. The process shows that we should work either in a divergent way, or in a convergent way. When we work in a divergent way, we look for possibilities and when we work in a convergent way we decide which of these possibilities are the best.
The original version of the Double Diamond had another point which makes it great: it's damn easy to remember and share. The look of the process is already in the name, and you could draw the process easily on the back of a napkin to explain how you'll work.
This process, like the Stanford D. School Design Thinking process, is also one of the most well know design processes out there. It means that many other processes are based on this one. So if you are a bit lazy, and also smart, take some time to explore in depth these two processes and you'll already understand many others.
Go deeper
You can find the original version of the Double Diamond on its Wikipedia page.
I found the updated version of the process in an article called "What is the framework for innovation? Design Council's evolved Double Diamond" on the Design Council website.
If you want to go further, you can also read the research paper called "The design process: Eleven lessons: managing design in eleven global brands" published by the same folks.
Finally if you want more historical information I recommend you read this other article from the Design Council website called "The Double Diamond: 15 years on".
Derivates
There are loads of derivates of the Double Diamond, I'll just add on here shared by the lovely Jochem van der Vee where the team at TheyDo adds a feedback loop to the Double Diamond. This shows us once more, than any process can be tweaked and adapted to fit the need of your project, company or mindset.