@@ -36,6 +36,7 @@ The lists below are ordered roughly by the number of users each change is expect
 * [`no-inner-declarations` has a new default behavior with a new option](#no-inner-declarations)
 * [`no-unused-vars` now defaults `caughtErrors` to `"all"`](#no-unused-vars)
 * [`no-useless-computed-key` flags unnecessary computed member names in classes by default](#no-useless-computed-key)
+* [`camelcase` allow option only accepts an array of strings](#camelcase)
 
 ### Breaking changes for plugin developers
 
@@ -434,6 +435,14 @@ class SomeClass {
 
 **Related issue(s):** [#18042](https://github.com/eslint/eslint/issues/18042)
 
+## <a name="camelcase"></a> `camelcase` allow option only accepts an array of strings
+
+Previously the camelcase rule didn't enforce the `allow` option to be an array of strings. In ESLint v9.0.0, the `allow` option now only accepts an array of strings.
+
+**To address:** If ESLint reports invalid configuration for this rule, update your configuration.
+
+**Related issue(s):** [#18232](https://github.com/eslint/eslint/pull/18232)
+
 ## <a name="removed-context-methods"></a> Removed multiple `context` methods
 
 ESLint v9.0.0 removes multiple deprecated methods from the `context` object and moves them onto the `SourceCode` object:
 
@@ -47,11 +47,9 @@ module.exports = {
                     },
                     allow: {
                         type: "array",
-                        items: [
-                            {
-                                type: "string"
-                            }
-                        ],
+                        items: {
+                            type: "string"
+                        },
                         minItems: 0,
                         uniqueItems: true
                     }
 
@@ -337,6 +337,18 @@ ruleTester.run("camelcase", rule, {
             code: "__option_foo__ = 0;",
             options: [{ allow: ["__option_foo__"] }]
         },
+        {
+            code: "__option_foo__ = 0; user_id = 0; foo = 1",
+            options: [{ allow: ["__option_foo__", "_id$"] }]
+        },
+        {
+            code: "fo_o = 0;",
+            options: [{ allow: ["__option_foo__", "fo_o"] }]
+        },
+        {
+            code: "user = 0;",
+            options: [{ allow: [] }]
+        },
         {
             code: "foo = { [computedBar]: 0 };",
             options: [{ ignoreDestructuring: true }],