Merge branch '5.next' into 6.x

Author: josbeir

toc_en.json

@@ -412,6 +412,10 @@
               "text": "5.3 Migration Guide",
               "link": "/appendices/5-3-migration-guide"
             },
+            {
+              "text": "5.4 Migration Guide",
+              "link": "/appendices/5-4-migration-guide"
+            },
             {
               "text": "CakePHP Development Process",
               "link": "/appendices/cakephp-development-process"