diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a838cf1..f4df4b3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
 
             -   uses: pnpm/action-setup@v3
                 with:
-                    version: 'latest'
+                    version: '10'
                     run_install: true
 
             # no need to check this separately, see below
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index cfd82ab..4c415d5 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -31,7 +31,7 @@ jobs:
 
             -   uses: pnpm/action-setup@v3
                 with:
-                    version: 'latest'
+                    version: '10'
                     run_install: true
 
             -   name: Set version number in package.json
diff --git a/CHANGELOG.md b/CHANGELOG.md
index afcf48d..2d6bad2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+2.8.2
+=====
+
+* (bug) Wrap `z.unknown()` with `z.optional()` in `errorSchema.data`, due changes in zod (unknown is now NonOptional).
+
+
 2.8.1
 =====
 
diff --git a/package.json b/package.json
index d37ba7f..93fc678 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
 		"test": "pnpm run build && cd dist && pnpm version '2.0.0-dummy' --no-git-tag-version && npm pack --dry-run && publint"
 	},
 	"dependencies": {
-		"zod": "^4.3.6"
+		"zod": "^4.4.3"
 	},
 	"optionalDependencies": {
 		"next": "^15.5.12 || ^16.1.6",
diff --git a/src/api.ts b/src/api.ts
index f3c35a9..e2b5f47 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -5,7 +5,7 @@ const errorSchema = z.object({
 	ok: z.literal(false),
 	error: z.optional(z.string()),
 	errorMessage: z.optional(z.string()),
-	data: z.unknown(),
+	data: z.optional(z.unknown()),
 });
 
 type Logger = Readonly<{