diff --git a/CONTRIBUTING.MD b/CONTRIBUTING.MD
index a77eaee..a62b973 100644
--- a/CONTRIBUTING.MD
+++ b/CONTRIBUTING.MD
@@ -7,4 +7,9 @@ Please, when making any changes, make a new branch. Start the branch name with o
 - `docs/`
 - `refactor/`
 
-For example `docs/update-uml-diagrams`.
\ No newline at end of file
+For example `docs/update-uml-diagrams`.
+
+### UML
+When changing anything in the code structure. You have to update the UML class diagram and relevant sequence diagrams.
+
+The UML diagrams shall always reflect the current state of the codebase.
\ No newline at end of file