diff --git a/IDEAS.md b/IDEAS.md
index d663ddbe..e9f1bb2c 100644
--- a/IDEAS.md
+++ b/IDEAS.md
@@ -20,6 +20,7 @@ let trimContract: S.contract<string => string> = S.contract(s => {
 
 ## v9
 
+- deepStrict for js/ts
 - Update documentation:
   - Add Enums section to js docs
 
diff --git a/package.json b/package.json
index f541ce44..d7d3fb60 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "rescript-schema",
-  "version": "8.4.0",
+  "version": "9.0.0-rc.1",
   "description": "🧬 The fastest parser in the entire JavaScript ecosystem with a focus on small bundle size and top-notch DX",
   "keywords": [
     "ReScript",
@@ -83,7 +83,7 @@
     "ts-expect": "1.3.0",
     "ts-node": "10.9.1",
     "typescript": "4.9.3",
-    "valibot": "0.36.0",
+    "valibot": "0.42.1",
     "zod": "3.23.8"
   },
   "peerDependencies": {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1f380a4f..4587dabe 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -42,8 +42,8 @@ importers:
         specifier: 4.9.3
         version: 4.9.3
       valibot:
-        specifier: 0.36.0
-        version: 0.36.0
+        specifier: 0.42.1
+        version: 0.42.1(typescript@4.9.3)
       zod:
         specifier: 3.23.8
         version: 3.23.8
@@ -994,6 +994,14 @@ packages:
   valibot@0.36.0:
     resolution: {integrity: sha512-CjF1XN4sUce8sBK9TixrDqFM7RwNkuXdJu174/AwmQUB62QbCQADg5lLe8ldBalFgtj1uKj+pKwDJiNo4Mn+eQ==}
 
+  valibot@0.42.1:
+    resolution: {integrity: sha512-3keXV29Ar5b//Hqi4MbSdV7lfVp6zuYLZuA9V1PvQUsXqogr+u5lvLPLk3A4f74VUXDnf/JfWMN6sB+koJ/FFw==}
+    peerDependencies:
+      typescript: '>=5'
+    peerDependenciesMeta:
+      typescript:
+        optional: true
+
   well-known-symbols@2.0.0:
     resolution: {integrity: sha512-ZMjC3ho+KXo0BfJb7JgtQ5IBuvnShdlACNkKkdsqBmYw3bPAaJfPeYUo6tLUaT5tG/Gkh7xkpBhKRQ9e7pyg9Q==}
     engines: {node: '>=6'}
@@ -1857,6 +1865,10 @@ snapshots:
 
   valibot@0.36.0: {}
 
+  valibot@0.42.1(typescript@4.9.3):
+    optionalDependencies:
+      typescript: 4.9.3
+
   well-known-symbols@2.0.0: {}
 
   which@2.0.2: