diff --git a/cases/arktype.ts b/cases/arktype.ts
index be39e59f8..3262d21fa 100644
--- a/cases/arktype.ts
+++ b/cases/arktype.ts
@@ -1,21 +1,91 @@
-import { type } from 'arktype';
+import { ArkErrors, type } from 'arktype';
 import { createCase } from '../benchmarks';
 
-const t = type({
-  number: 'number',
-  negNumber: 'number',
-  maxNumber: 'number',
-  string: 'string',
-  longString: 'string',
-  boolean: 'boolean',
-  deeplyNested: {
-    foo: 'string',
-    num: 'number',
-    bool: 'boolean',
-  },
+// As of version 2.1.9, the test fails because of a mutation attempt
+// createCase('arktype', 'parseSafe', () => {
+//   const t = type({
+//     '+': 'delete',
+//     number: 'number',
+//     negNumber: 'number',
+//     maxNumber: 'number',
+//     string: 'string',
+//     longString: 'string',
+//     boolean: 'boolean',
+//     deeplyNested: {
+//       '+': 'delete',
+//       foo: 'string',
+//       num: 'number',
+//       bool: 'boolean',
+//     },
+//   });
+//   return data => {
+//     const r = t(data);
+//     if (r instanceof ArkErrors) throw r;
+//     return r;
+//   };
+// });
+
+createCase('arktype', 'parseStrict', () => {
+  const t = type({
+    '+': 'reject',
+    number: 'number',
+    negNumber: 'number',
+    maxNumber: 'number',
+    string: 'string',
+    longString: 'string',
+    boolean: 'boolean',
+    deeplyNested: {
+      '+': 'reject',
+      foo: 'string',
+      num: 'number',
+      bool: 'boolean',
+    },
+  });
+  return data => {
+    const r = t(data);
+    if (r instanceof ArkErrors) throw r;
+    return r;
+  };
 });
 
 createCase('arktype', 'assertLoose', () => {
+  const t = type({
+    number: 'number',
+    negNumber: 'number',
+    maxNumber: 'number',
+    string: 'string',
+    longString: 'string',
+    boolean: 'boolean',
+    deeplyNested: {
+      foo: 'string',
+      num: 'number',
+      bool: 'boolean',
+    },
+  });
+
+  return data => {
+    if (t.allows(data)) return true;
+    throw new Error('Invalid');
+  };
+});
+
+createCase('arktype', 'assertStrict', () => {
+  const t = type({
+    '+': 'reject',
+    number: 'number',
+    negNumber: 'number',
+    maxNumber: 'number',
+    string: 'string',
+    longString: 'string',
+    boolean: 'boolean',
+    deeplyNested: {
+      '+': 'reject',
+      foo: 'string',
+      num: 'number',
+      bool: 'boolean',
+    },
+  });
+
   return data => {
     if (t.allows(data)) return true;
     throw new Error('Invalid');
diff --git a/package-lock.json b/package-lock.json
index 658cb0d59..893e689d4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -27,7 +27,7 @@
         "@types/benchmark": "2.1.5",
         "@vbudovski/paseri": "npm:@jsr/vbudovski__paseri@0.1.18",
         "ajv": "8.17.1",
-        "arktype": "2.0.0-dev.12-cjs",
+        "arktype": "2.1.9",
         "banditypes": "0.2.5",
         "benny": "3.7.1",
         "bueno": "0.1.5",
@@ -177,19 +177,20 @@
         "node": ">=6.0.0"
       }
     },
-    "node_modules/@arktype/schema": {
-      "version": "0.1.4-cjs",
-      "resolved": "https://registry.npmjs.org/@arktype/schema/-/schema-0.1.4-cjs.tgz",
-      "integrity": "sha512-mk/9CoASlEl3NQErqc9WMfs7cGiy4BdQpsmOKqWZHIpnuzvn59XbzXZ3LXtEylIOOovPvplP1VndPkiZhb8v0Q==",
+    "node_modules/@ark/schema": {
+      "version": "0.44.4",
+      "resolved": "https://registry.npmjs.org/@ark/schema/-/schema-0.44.4.tgz",
+      "integrity": "sha512-TsZTX+k5J7xsGABsFjVdRUNgViGDMLv73sikBM8JNxC4STe0suTuMNa1OJ/AFP2N+LpJ1zL9tdWlg28PRqAYhg==",
       "license": "MIT",
       "dependencies": {
-        "@arktype/util": "0.0.41-cjs"
+        "@ark/util": "0.44.4"
       }
     },
-    "node_modules/@arktype/util": {
-      "version": "0.0.41-cjs",
-      "resolved": "https://registry.npmjs.org/@arktype/util/-/util-0.0.41-cjs.tgz",
-      "integrity": "sha512-JuijNPUx7CSGhw36+z12mrzsR2bRmqeL5W/h0kWlR+hUCgqNc4GLY8JRL5ERg2GwidDQCVe4lvJOpiPffuOCrQ=="
+    "node_modules/@ark/util": {
+      "version": "0.44.4",
+      "resolved": "https://registry.npmjs.org/@ark/util/-/util-0.44.4.tgz",
+      "integrity": "sha512-zLfNZrsq5Dq+8B0pHJwL/wD3xNBHb8FoP0FuPB455w7HpqVaqO5qPXvn+YoO8v1Y6pNwLVsM9vCIiO221LoODQ==",
+      "license": "MIT"
     },
     "node_modules/@arrows/array": {
       "version": "1.4.1",
@@ -3857,13 +3858,13 @@
       "integrity": "sha512-PYjyFOLKQ9y57JvQ6QLo8dAgNqswh8M1RMJYdQduT6xbWSgK36P/Z/v+p888pM69jMMfS8Xd8F6I1kQ/I9HUGg=="
     },
     "node_modules/arktype": {
-      "version": "2.0.0-dev.12-cjs",
-      "resolved": "https://registry.npmjs.org/arktype/-/arktype-2.0.0-dev.12-cjs.tgz",
-      "integrity": "sha512-bACCf7FLER9H3e7NY/aaxQwlUK3e36PjLRbbOgwDQiXJ2cE5EOFwb30JAt8uoFL2fFBTHipnDOhxoincUI2Ogw==",
+      "version": "2.1.9",
+      "resolved": "https://registry.npmjs.org/arktype/-/arktype-2.1.9.tgz",
+      "integrity": "sha512-bq46shcLpfop4D9acVQN/+quZ+hIGs4OUzoLq2vCaZLdkITOlWkfamBk9abMuC6fbgxW1fu/2PamcQgggWhTwQ==",
       "license": "MIT",
       "dependencies": {
-        "@arktype/schema": "0.1.4-cjs",
-        "@arktype/util": "0.0.41-cjs"
+        "@ark/schema": "0.44.4",
+        "@ark/util": "0.44.4"
       }
     },
     "node_modules/array-back": {
@@ -11233,18 +11234,18 @@
         "@jridgewell/trace-mapping": "^0.3.9"
       }
     },
-    "@arktype/schema": {
-      "version": "0.1.4-cjs",
-      "resolved": "https://registry.npmjs.org/@arktype/schema/-/schema-0.1.4-cjs.tgz",
-      "integrity": "sha512-mk/9CoASlEl3NQErqc9WMfs7cGiy4BdQpsmOKqWZHIpnuzvn59XbzXZ3LXtEylIOOovPvplP1VndPkiZhb8v0Q==",
+    "@ark/schema": {
+      "version": "0.44.4",
+      "resolved": "https://registry.npmjs.org/@ark/schema/-/schema-0.44.4.tgz",
+      "integrity": "sha512-TsZTX+k5J7xsGABsFjVdRUNgViGDMLv73sikBM8JNxC4STe0suTuMNa1OJ/AFP2N+LpJ1zL9tdWlg28PRqAYhg==",
       "requires": {
-        "@arktype/util": "0.0.41-cjs"
+        "@ark/util": "0.44.4"
       }
     },
-    "@arktype/util": {
-      "version": "0.0.41-cjs",
-      "resolved": "https://registry.npmjs.org/@arktype/util/-/util-0.0.41-cjs.tgz",
-      "integrity": "sha512-JuijNPUx7CSGhw36+z12mrzsR2bRmqeL5W/h0kWlR+hUCgqNc4GLY8JRL5ERg2GwidDQCVe4lvJOpiPffuOCrQ=="
+    "@ark/util": {
+      "version": "0.44.4",
+      "resolved": "https://registry.npmjs.org/@ark/util/-/util-0.44.4.tgz",
+      "integrity": "sha512-zLfNZrsq5Dq+8B0pHJwL/wD3xNBHb8FoP0FuPB455w7HpqVaqO5qPXvn+YoO8v1Y6pNwLVsM9vCIiO221LoODQ=="
     },
     "@arrows/array": {
       "version": "1.4.1",
@@ -13635,12 +13636,12 @@
       "integrity": "sha512-PYjyFOLKQ9y57JvQ6QLo8dAgNqswh8M1RMJYdQduT6xbWSgK36P/Z/v+p888pM69jMMfS8Xd8F6I1kQ/I9HUGg=="
     },
     "arktype": {
-      "version": "2.0.0-dev.12-cjs",
-      "resolved": "https://registry.npmjs.org/arktype/-/arktype-2.0.0-dev.12-cjs.tgz",
-      "integrity": "sha512-bACCf7FLER9H3e7NY/aaxQwlUK3e36PjLRbbOgwDQiXJ2cE5EOFwb30JAt8uoFL2fFBTHipnDOhxoincUI2Ogw==",
+      "version": "2.1.9",
+      "resolved": "https://registry.npmjs.org/arktype/-/arktype-2.1.9.tgz",
+      "integrity": "sha512-bq46shcLpfop4D9acVQN/+quZ+hIGs4OUzoLq2vCaZLdkITOlWkfamBk9abMuC6fbgxW1fu/2PamcQgggWhTwQ==",
       "requires": {
-        "@arktype/schema": "0.1.4-cjs",
-        "@arktype/util": "0.0.41-cjs"
+        "@ark/schema": "0.44.4",
+        "@ark/util": "0.44.4"
       }
     },
     "array-back": {
diff --git a/package.json b/package.json
index 552b31677..acd478d93 100644
--- a/package.json
+++ b/package.json
@@ -49,7 +49,7 @@
     "@types/benchmark": "2.1.5",
     "@vbudovski/paseri": "npm:@jsr/vbudovski__paseri@0.1.18",
     "ajv": "8.17.1",
-    "arktype": "2.0.0-dev.12-cjs",
+    "arktype": "2.1.9",
     "banditypes": "0.2.5",
     "benny": "3.7.1",
     "bueno": "0.1.5",