diff --git a/en_us/viki.json b/en_us/viki.json
index 96071b4f..bee90bf1 100644
--- a/en_us/viki.json
+++ b/en_us/viki.json
@@ -15,7 +15,7 @@
         "typographer": false,
         "lang_prefix": "lang-",
         "image_caption": true,
-        "plantuml_server": "http://www.plantuml.com/plantuml",
+        "plantuml_server": "https://www.plantuml.com/plantuml",
         "plantuml_format": "svg",
         "code_block_line_number": false
     }
diff --git a/zh_cn/viki.json b/zh_cn/viki.json
index 20b1a97f..6fc0aa26 100644
--- a/zh_cn/viki.json
+++ b/zh_cn/viki.json
@@ -15,7 +15,7 @@
         "typographer": false,
         "lang_prefix": "lang-",
         "image_caption": true,
-        "plantuml_server": "http://www.plantuml.com/plantuml",
+        "plantuml_server": "https://www.plantuml.com/plantuml",
         "plantuml_format": "svg",
         "code_block_line_number": false
     }