diff --git a/html/elements/details.json b/html/elements/details.json
index 704904e13e926e..fe847004b9817f 100644
--- a/html/elements/details.json
+++ b/html/elements/details.json
@@ -37,7 +37,7 @@
               "version_added": "15"
             },
             "opera_android": {
-              "version_added": null
+              "version_added": "14"
             },
             "safari": {
               "version_added": "6"
@@ -88,7 +88,7 @@
                 "version_added": "15"
               },
               "opera_android": {
-                "version_added": null
+                "version_added": "14"
               },
               "safari": {
                 "version_added": "6"
diff --git a/html/elements/summary.json b/html/elements/summary.json
index d975ffaa78e801..18396d5ae3bd07 100644
--- a/html/elements/summary.json
+++ b/html/elements/summary.json
@@ -32,10 +32,10 @@
               "version_added": false
             },
             "opera": {
-              "version_added": false
+              "version_added": "15"
             },
             "opera_android": {
-              "version_added": false
+              "version_added": "14"
             },
             "safari": {
               "version_added": "6"