diff --git a/src/utils/config/yaml.js b/src/utils/config/yaml.js
index f8125ab11..6266689bd 100644
--- a/src/utils/config/yaml.js
+++ b/src/utils/config/yaml.js
@@ -1,7 +1,7 @@
 import * as yaml from "js-yaml";
 
 const EMPTY_DOCUMENT_ERROR = "expected a document, but the input is empty";
-const DEFAULT_SCHEMA = yaml.CORE_SCHEMA.withTags(yaml.timestampTag, yaml.mergeTag);
+const DEFAULT_SCHEMA = yaml.CORE_SCHEMA.withTags(yaml.timestampTag, yaml.mergeTag, yaml.legacyMapTag);
 
 export function loadYaml(input, options) {
   try {
diff --git a/src/utils/config/yaml.test.js b/src/utils/config/yaml.test.js
index 4af6b7b3a..aa437a62e 100644
--- a/src/utils/config/yaml.test.js
+++ b/src/utils/config/yaml.test.js
@@ -25,6 +25,16 @@ describe("utils/config/yaml", () => {
     });
   });
 
+  it("preserves v4 handling of non-string keys", () => {
+    // an unsubstituted {{HOMEPAGE_VAR_*}} parses as a flow mapping key
+    expect(loadYaml("- Plex:\n    widget:\n      key: {{HOMEPAGE_VAR_PLEX_KEY}}\n")).toEqual([
+      { Plex: { widget: { key: { "[object Object]": null } } } },
+    ]);
+    expect(loadYaml("- Backups:\n    - 2024-01-01:\n        href: http://x\n")).toEqual([
+      { Backups: [{ [String(new Date("2024-01-01T00:00:00.000Z"))]: { href: "http://x" } }] },
+    ]);
+  });
+
   it("still rejects invalid YAML", () => {
     expect(() => loadYaml("value: [\n")).toThrow();
   });