diff --git a/docs/configuration.rst b/docs/configuration.rst
index 2aed705e..68a97438 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -4408,19 +4408,6 @@ Description
     When more than one format is given, the first available one is selected.
 
 
-extractor.sankaku.id-format
----------------------------
-Type
-    ``string``
-Default
-    ``"numeric"``
-Description
-    Format of ``id`` metadata fields.
-
-    * ``"alphanumeric"`` or ``"alnum"``: 11-character alphanumeric IDs (``y0abGlDOr2o``)
-    * ``"numeric"`` or ``"legacy"``: numeric IDs (``360451``)
-
-
 extractor.sankaku.refresh
 -------------------------
 Type
diff --git a/docs/gallery-dl.conf b/docs/gallery-dl.conf
index 222418f3..3a3c6555 100644
--- a/docs/gallery-dl.conf
+++ b/docs/gallery-dl.conf
@@ -591,7 +591,6 @@
             "username": "",
             "password": "",
 
-            "id-format": "numeric",
             "refresh"  : false,
             "tags"     : false
         },
diff --git a/gallery_dl/extractor/sankaku.py b/gallery_dl/extractor/sankaku.py
index a338e795..fcd53872 100644
--- a/gallery_dl/extractor/sankaku.py
+++ b/gallery_dl/extractor/sankaku.py
@@ -216,9 +216,6 @@ class SankakuAPI():
             "Origin"     : extractor.root,
         }
 
-        if extractor.config("id-format") in ("alnum", "alphanumeric"):
-            self.headers["Api-Version"] = "2"
-
         self.username, self.password = extractor._get_auth_info()
         if not self.username:
             self.authenticate = util.noop