diff --git a/api/CanvasRenderingContext2D.json b/api/CanvasRenderingContext2D.json
index a4bf0c58f479dd..4cbe31361c2507 100644
--- a/api/CanvasRenderingContext2D.json
+++ b/api/CanvasRenderingContext2D.json
@@ -1239,9 +1239,17 @@
             "opera_android": {
               "version_added": "≤12.1"
             },
-            "safari": {
-              "version_added": "4"
-            },
+            "safari": [
+              {
+                "version_added": "18.4"
+              },
+              {
+                "version_added": "4",
+                "version_removed": "18.4",
+                "partial_implementation": true,
+                "notes": "The `font-weight` can be set, but is not reflected back (see [bug 284115](https://webkit.org/b/284115))."
+              }
+            ],
             "safari_ios": "mirror",
             "samsunginternet_android": "mirror",
             "webview_android": {
diff --git a/api/OffscreenCanvasRenderingContext2D.json b/api/OffscreenCanvasRenderingContext2D.json
index 7823301757adf9..a56f8975a165d4 100644
--- a/api/OffscreenCanvasRenderingContext2D.json
+++ b/api/OffscreenCanvasRenderingContext2D.json
@@ -897,9 +897,17 @@
             "oculus": "mirror",
             "opera": "mirror",
             "opera_android": "mirror",
-            "safari": {
-              "version_added": "16.4"
-            },
+            "safari": [
+              {
+                "version_added": "18.4"
+              },
+              {
+                "version_added": "16.4",
+                "version_removed": "18.4",
+                "partial_implementation": true,
+                "notes": "The `font-weight` can be set, but is not reflected back (see [bug 284115](https://webkit.org/b/284115))."
+              }
+            ],
             "safari_ios": "mirror",
             "samsunginternet_android": "mirror",
             "webview_android": "mirror",