Update BRANCHES.md

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/BRANCHES.md b/BRANCHES.md
index 49f7e28..78f8f69 100644
--- a/BRANCHES.md
+++ b/BRANCHES.md
@@ -106,6 +106,6 @@
 - [`development`](https://github.com/Mbed-TLS/mbedtls/)
 - [`mbedtls-3.6`](https://github.com/Mbed-TLS/mbedtls/tree/mbedtls-3.6)
  maintained until March 2027, see
-  <https://github.com/Mbed-TLS/mbedtls/releases/tag/v3.6.0>.
+  <https://github.com/Mbed-TLS/mbedtls/releases/tag/v3.6.4>.
 
 Users are urged to always use the latest version of a maintained branch.