diff --git a/doc/api/README.md b/doc/api/README.md
index 20f28e8d30ea460849fab04c9f5bbd91c7355a31..b334ca46caf926b1fe74f392386b93424f8b715d 100644
--- a/doc/api/README.md
+++ b/doc/api/README.md
@@ -49,6 +49,7 @@ following locations:
 - [Todos](todos.md)
 - [Users](users.md)
 - [Validate CI configuration](ci/lint.md)
+- [V3 to V4](v3_to_v4.md)
 - [Version](version.md)
 
 ### Internal CI API
diff --git a/doc/api/v3_to_v4.md b/doc/api/v3_to_v4.md
new file mode 100644
index 0000000000000000000000000000000000000000..01de1e59fcbbdbc78936da899b72e0b1c12d5b6a
--- /dev/null
+++ b/doc/api/v3_to_v4.md
@@ -0,0 +1,10 @@
+# V3 to V4 version
+
+Our V4 API version is currently available as *Beta*! It means that V3
+will still be supported and remain unchanged for now, but be aware that the following
+changes are in V4:
+
+### Changes
+
+- Removed `/projects/:search` (use: `/projects?search=x`)
+