diff --git a/app/components/device/new/new-device-stepper.tsx b/app/components/device/new/new-device-stepper.tsx
index 5ed8b0b91..58f81aa34 100644
--- a/app/components/device/new/new-device-stepper.tsx
+++ b/app/components/device/new/new-device-stepper.tsx
@@ -36,7 +36,7 @@ const generalInfoSchema = z.object({
 		.min(2, 'Name must be at least 2 characters')
 		.min(1, 'Name is required'),
 	exposure: z.enum(['indoor', 'outdoor', 'mobile', 'unknown'], {
-		errorMap: () => ({ message: 'Exposure is required' }),
+		error: () => 'Exposure is required',
 	}),
 	temporaryExpirationDate: z
 		.string()
@@ -46,8 +46,8 @@ const generalInfoSchema = z.object({
 			(date) =>
 				!date || date <= new Date(Date.now() + 31 * 24 * 60 * 60 * 1000),
 			{
-				message: 'Temporary expiration date must be within 1 month from now',
-			},
+                error: 'Temporary expiration date must be within 1 month from now'
+            },
 		),
 	tags: z
 		.array(
@@ -61,23 +61,21 @@ const generalInfoSchema = z.object({
 const locationSchema = z.object({
 	latitude: z.coerce
 		.number({
-			invalid_type_error: 'Latitude must be a valid number',
-			required_error: 'Latitude is required',
-		})
+            error: (issue) => issue.input === undefined ? 'Latitude is required' : 'Latitude must be a valid number'
+        })
 		.min(-90, 'Latitude must be greater than or equal to -90')
 		.max(90, 'Latitude must be less than or equal to 90'),
 	longitude: z.coerce
 		.number({
-			invalid_type_error: 'Longitude must be a valid number',
-			required_error: 'Longitude is required',
-		})
+            error: (issue) => issue.input === undefined ? 'Longitude is required' : 'Longitude must be a valid number'
+        })
 		.min(-180, 'Longitude must be greater than or equal to -180')
 		.max(180, 'Longitude must be less than or equal to 180'),
 })
 
 const deviceSchema = z.object({
 	model: z.enum(DeviceModelEnum.enumValues, {
-		errorMap: () => ({ message: 'Please select a device.' }),
+		error: () => 'Please select a device.',
 	}),
 })
 
@@ -88,7 +86,7 @@ const sensorsSchema = z.object({
 		.min(1, 'Please select at least one sensor'),
 })
 
-const advancedSchema = z.record(z.any())
+const advancedSchema = z.record(z.string(), z.any())
 
 export const Stepper = defineStepper(
 	{
diff --git a/app/lib/api-schemas/boxes-data-query-schema.ts b/app/lib/api-schemas/boxes-data-query-schema.ts
index d946b5c26..a5c648f69 100644
--- a/app/lib/api-schemas/boxes-data-query-schema.ts
+++ b/app/lib/api-schemas/boxes-data-query-schema.ts
@@ -36,8 +36,8 @@ const BoxesDataQuerySchemaBase = z
 					.transform((arr) => arr.map((x) => Number(x))),
 			])
 			.refine((arr) => arr.length === 4 && arr.every((n) => !isNaN(n)), {
-				message: 'bbox must contain exactly 4 numeric coordinates',
-			})
+                error: 'bbox must contain exactly 4 numeric coordinates'
+            })
 			.optional(),
 
 		exposure: z
@@ -61,26 +61,26 @@ const BoxesDataQuerySchemaBase = z
 			.string()
 			.transform((s) => new Date(s))
 			.refine((d) => !isNaN(d.getTime()), {
-				message: 'from-date is invalid',
-			})
+                error: 'from-date is invalid'
+            })
 			.optional()
-			.default(() =>
+			.prefault(() =>
 				new Date(Date.now() - 2 * 24 * 60 * 60 * 1000).toISOString(),
 			),
 		toDate: z
 			.string()
 			.transform((s) => new Date(s))
 			.refine((d) => !isNaN(d.getTime()), {
-				message: 'to-date is invalid',
-			})
+                error: 'to-date is invalid'
+            })
 			.optional()
-			.default(() => new Date().toISOString()),
+			.prefault(() => new Date().toISOString()),
 
 		format: z
 			.enum(['csv', 'json'], {
-				errorMap: () => ({ message: "Format must be either 'csv' or 'json'" }),
+				error: () => "Format must be either 'csv' or 'json'",
 			})
-			.default('csv'),
+			.prefault('csv'),
 
 		// Columns to include
 		columns: z
@@ -96,7 +96,7 @@ const BoxesDataQuerySchemaBase = z
 						arr.map((s) => String(s).trim() as BoxesDataColumn),
 					),
 			])
-			.default([
+			.prefault([
 				'sensorId',
 				'createdAt',
 				'value',
@@ -110,15 +110,15 @@ const BoxesDataQuerySchemaBase = z
 				if (typeof v === 'boolean') return v
 				return v !== 'false' && v !== '0'
 			})
-			.default(true),
+			.prefault(true),
 
-		delimiter: z.enum(['comma', 'semicolon']).default('comma'),
+		delimiter: z.enum(['comma', 'semicolon']).prefault('comma'),
 	})
 	// Validate: must have boxid or bbox, but not both
 	.superRefine((data, ctx) => {
 		if (!data.boxid && !data.bbox && !data.grouptag) {
 			ctx.addIssue({
-				code: z.ZodIssueCode.custom,
+				code: "custom",
 				message: 'please specify either boxid, bbox or grouptag',
 				path: ['boxid'],
 			})
@@ -126,7 +126,7 @@ const BoxesDataQuerySchemaBase = z
 
 		if (!data.phenomenon && !data.grouptag) {
 			ctx.addIssue({
-				code: z.ZodIssueCode.custom,
+				code: "custom",
 				message:
 					'phenomenon parameter is required when grouptag is not provided',
 				path: ['phenomenon'],
@@ -163,7 +163,7 @@ export async function parseBoxesDataQuery(
 	const parseResult = BoxesDataQuerySchemaBase.safeParse(params)
 
 	if (!parseResult.success) {
-		const firstError = parseResult.error.errors[0]
+		const firstError = parseResult.error.issues[0]
 		const message = firstError.message || 'Invalid query parameters'
 
 		if (firstError.path.includes('bbox')) {
diff --git a/app/lib/devices-service.server.ts b/app/lib/devices-service.server.ts
index 2dc4ff71d..900cb0d51 100644
--- a/app/lib/devices-service.server.ts
+++ b/app/lib/devices-service.server.ts
@@ -8,11 +8,11 @@ export const CreateBoxSchema = z.object({
 	exposure: z
 		.enum(['indoor', 'outdoor', 'mobile', 'unknown'])
 		.optional()
-		.default('unknown'),
+		.prefault('unknown'),
 	location: z
 		.array(z.number())
 		.length(2, 'Location must be [longitude, latitude]'),
-	grouptag: z.array(z.string()).optional().default([]),
+	grouptag: z.array(z.string()).optional().prefault([]),
 	model: z
 		.enum([
 			'homeV2Lora',
@@ -23,7 +23,7 @@ export const CreateBoxSchema = z.object({
 			'custom',
 		])
 		.optional()
-		.default('custom'),
+		.prefault('custom'),
 	sensors: z
 		.array(
 			z.object({
@@ -35,32 +35,36 @@ export const CreateBoxSchema = z.object({
 			}),
 		)
 		.optional()
-		.default([]),
+		.prefault([]),
 })
 
 export const BoxesQuerySchema = z.object({
 	format: z
 		.enum(['json', 'geojson'], {
-			errorMap: () => ({
-				message: "Format must be either 'json' or 'geojson'",
-			}),
+			error: () => "Format must be either 'json' or 'geojson'",
 		})
-		.default('json'),
+		.prefault('json'),
 	minimal: z
 		.enum(['true', 'false'])
-		.default('false')
+		.prefault('false')
 		.transform((v) => v === 'true'),
 	full: z
 		.enum(['true', 'false'])
-		.default('false')
+		.prefault('false')
 		.transform((v) => v === 'true'),
 	limit: z
 		.string()
-		.default('5')
+		.prefault('5')
 		.transform((val) => parseInt(val, 10))
-		.refine((val) => !isNaN(val), { message: 'Limit must be a number' })
-		.refine((val) => val >= 1, { message: 'Limit must be at least 1' })
-		.refine((val) => val <= 20, { message: 'Limit must not exceed 20' }),
+		.refine((val) => !isNaN(val), {
+            error: 'Limit must be a number'
+        })
+		.refine((val) => val >= 1, {
+            error: 'Limit must be at least 1'
+        })
+		.refine((val) => val <= 20, {
+            error: 'Limit must not exceed 20'
+        }),
 
 	name: z.string().optional(),
 	date: z
@@ -111,8 +115,8 @@ export const BoxesQuerySchema = z.object({
 	near: z
 		.string()
 		.regex(/^[-+]?\d+(\.\d+)?,[-+]?\d+(\.\d+)?$/, {
-			message: "Invalid 'near' parameter format. Expected: 'lat,lng'",
-		})
+            error: "Invalid 'near' parameter format. Expected: 'lat,lng'"
+        })
 		.transform((val) => val.split(',').map(Number) as [number, number])
 		.optional(),
 
@@ -143,14 +147,10 @@ export const BoxesQuerySchema = z.object({
 		})
 		.optional(),
 
-	fromDate: z
-		.string()
-		.datetime()
+	fromDate: z.iso.datetime()
 		.transform((v) => new Date(v))
 		.optional(),
-	toDate: z
-		.string()
-		.datetime()
+	toDate: z.iso.datetime()
 		.transform((v) => new Date(v))
 		.optional(),
 })
diff --git a/app/routes/settings.profile.photo.tsx b/app/routes/settings.profile.photo.tsx
index 8b05a4f56..2deca503c 100644
--- a/app/routes/settings.profile.photo.tsx
+++ b/app/routes/settings.profile.photo.tsx
@@ -1,5 +1,5 @@
-import { conform, useForm } from '@conform-to/react'
-import { getFieldsetConstraint, parse } from '@conform-to/zod'
+import { useForm, getInputProps, getFormProps } from '@conform-to/react'
+import { getZodConstraint, parseWithZod } from '@conform-to/zod/v4'
 import { type FileUpload, parseFormData } from '@mjackson/form-data-parser'
 import { eq } from 'drizzle-orm'
 import { useState } from 'react'
@@ -14,7 +14,7 @@ import {
 	useLoaderData,
 	useNavigate,
 } from 'react-router'
-import { z } from 'zod'
+import { z } from 'zod/v4'
 import ErrorMessage from '~/components/error-message'
 import { LabelButton } from '~/components/label-button'
 import { Avatar, AvatarFallback, AvatarImage } from '~/components/ui/avatar'
@@ -74,17 +74,11 @@ export async function action({ request }: ActionFunctionArgs) {
 		async (file: FileUpload) => uploadHandler(file),
 	)
 
-	const submission = parse(formData, { schema: PhotoFormSchema })
+	const submission = parseWithZod(formData, { schema: PhotoFormSchema })
 
-	if (submission.intent !== 'submit') {
-		return { status: 'idle', submission } as const
-	}
-	if (!submission.value) {
+	if (submission.status !== 'success') {
 		return data(
-			{
-				status: 'error',
-				submission,
-			} as const,
+			{ status: 'error', submission: submission.reply() } as const,
 			{ status: 400 },
 		)
 	}
@@ -127,16 +121,18 @@ export default function PhotoChooserModal() {
 	const actionData = useActionData<typeof action>()
 	const [form, { photoFile }] = useForm({
 		id: 'profile-photo',
-		constraint: getFieldsetConstraint(PhotoFormSchema),
-		lastSubmission: actionData?.submission,
+		constraint: getZodConstraint(PhotoFormSchema),
+		lastResult: actionData?.submission,
 		onValidate({ formData }) {
-			return parse(formData, { schema: PhotoFormSchema })
+			return parseWithZod(formData, { schema: PhotoFormSchema })
 		},
 		shouldRevalidate: 'onBlur',
 	})
 
 	const { t } = useTranslation('settings')
 
+	const { key, ...photoFileProps } = getInputProps(photoFile, { type: 'file' })
+
 	const dismissModal = () => navigate('..', { preventScrollReset: true })
 	return (
 		<Dialog open={true} onOpenChange={dismissModal}>
@@ -149,11 +145,11 @@ export default function PhotoChooserModal() {
 					<DialogTitle>{t('profile_photo')}</DialogTitle>
 				</DialogHeader>
 				<Form
+					{...getFormProps(form)}
 					method="post"
 					encType="multipart/form-data"
 					className="mt-8 flex flex-col items-center justify-center gap-10"
 					onReset={() => setNewImageSrc(null)}
-					{...form.props}
 				>
 					<Avatar className="h-64 w-64">
 						<AvatarImage
@@ -170,7 +166,8 @@ export default function PhotoChooserModal() {
 					</Avatar>
 					{/* <ErrorList errors={photoFile.errors} id={photoFile.id} /> */}
 					<input
-						{...conform.input(photoFile, { type: 'file' })}
+						key={key}
+						{...photoFileProps}
 						type="file"
 						accept="image/*"
 						className="sr-only"
diff --git a/app/utils/env.server.ts b/app/utils/env.server.ts
index 6be4425ce..4c2f4df0d 100644
--- a/app/utils/env.server.ts
+++ b/app/utils/env.server.ts
@@ -5,13 +5,13 @@ const schema = z.object({
   DATABASE_URL: z.string(),
   PG_CLIENT_SSL: z.string(),
   SESSION_SECRET: z.string(),
-  MAPBOX_GEOCODING_API: z.string().url(),
+  MAPBOX_GEOCODING_API: z.url(),
   MAPBOX_ACCESS_TOKEN: z.string(),
-  OSEM_API_URL: z.string().url(),
-  DIRECTUS_URL: z.string().url(),
-  SENSORWIKI_API_URL: z.string().url(),
-  MYBADGES_API_URL: z.string().url(),
-  MYBADGES_URL: z.string().url(),
+  OSEM_API_URL: z.url(),
+  DIRECTUS_URL: z.url(),
+  SENSORWIKI_API_URL: z.url(),
+  MYBADGES_API_URL: z.url(),
+  MYBADGES_URL: z.url(),
   MYBADGES_SERVERADMIN_USERNAME: z.string(),
   MYBADGES_SERVERADMIN_PASSWORD: z.string(),
   MYBADGES_ISSUERID_OSEM: z.string(),
@@ -31,7 +31,7 @@ export function init() {
 	if (parsed.success === false) {
 		console.error(
 			'❌ Invalid environment variables:',
-			parsed.error.flatten().fieldErrors,
+			z.treeifyError(parsed.error),
 		)
 	}
 }
diff --git a/app/utils/user-validation.ts b/app/utils/user-validation.ts
index 29bf4ba19..f4c183861 100644
--- a/app/utils/user-validation.ts
+++ b/app/utils/user-validation.ts
@@ -2,24 +2,40 @@ import { z } from 'zod'
 
 export const usernameSchema = z
 	.string()
-	.min(3, { message: 'Username is too short' })
-	.max(20, { message: 'Username is too long' })
+	.min(3, {
+        error: 'Username is too short'
+    })
+	.max(20, {
+        error: 'Username is too long'
+    })
 	.regex(/^[a-zA-Z0-9_]+$/, {
-		message: 'Username can only include letters, numbers, and underscores',
-	})
+        error: 'Username can only include letters, numbers, and underscores'
+    })
 
 export const passwordSchema = z
 	.string()
-	.min(6, { message: 'Password is too short' })
-	.max(100, { message: 'Password is too long' })
+	.min(6, {
+        error: 'Password is too short'
+    })
+	.max(100, {
+        error: 'Password is too long'
+    })
 
 export const nameSchema = z
 	.string()
-	.min(3, { message: 'Name is too short' })
-	.max(40, { message: 'Name is too long' })
+	.min(3, {
+        error: 'Name is too short'
+    })
+	.max(40, {
+        error: 'Name is too long'
+    })
 
-export const emailSchema = z
-	.string()
-	.email({ message: 'Email is invalid' })
-	.min(3, { message: 'Email is too short' })
-	.max(100, { message: 'Email is too long' })
+export const emailSchema = z.email({
+        error: 'Email is invalid'
+    })
+	.min(3, {
+        error: 'Email is too short'
+    })
+	.max(100, {
+        error: 'Email is too long'
+    })
diff --git a/db/env-schema.ts b/db/env-schema.ts
index 5d64bf199..b4a127ced 100644
--- a/db/env-schema.ts
+++ b/db/env-schema.ts
@@ -2,8 +2,8 @@ import 'dotenv/config'
 import { z } from 'zod'
 
 const envSchema = z.object({
-	DATABASE_URL: z.string().url().trim().min(1),
-	PG_CLIENT_SSL: z.string().default('false'),
+	DATABASE_URL: z.url().trim().min(1),
+	PG_CLIENT_SSL: z.string().prefault('false'),
 })
 
 const envDB = envSchema.safeParse(process.env)
diff --git a/package-lock.json b/package-lock.json
index 109cce244..cea4464dc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,8 +8,8 @@
       "dependencies": {
         "@aws-sdk/client-s3": "^3.971.0",
         "@aws-sdk/s3-request-presigner": "^3.971.0",
-        "@conform-to/react": "^0.9.2",
-        "@conform-to/zod": "^0.9.2",
+        "@conform-to/react": "^1.17.1",
+        "@conform-to/zod": "^1.17.1",
         "@directus/sdk": "^19.1.0",
         "@formatjs/intl": "^4.1.2",
         "@heroicons/react": "^2.2.0",
@@ -128,8 +128,8 @@
         "uuid": "^11.1.0",
         "vaul": "^1.1.2",
         "vite-plugin-markdown": "^2.2.0",
-        "zod": "^3.25.67",
-        "zod-form-data": "^2.0.8"
+        "zod": "^4.3.6",
+        "zod-form-data": "^3.0.1"
       },
       "devDependencies": {
         "@epic-web/config": "^1.21.0",
@@ -2725,31 +2725,33 @@
       }
     },
     "node_modules/@conform-to/dom": {
-      "version": "0.9.2",
-      "resolved": "https://registry.npmjs.org/@conform-to/dom/-/dom-0.9.2.tgz",
-      "integrity": "sha512-vYJvXMRxa9Ieslv5eVcak5+0QbcTv+HwdLqRPZ8lhSFZx5qQWJwdou+Iz+ERzsSQHh7QS3DDYG5HmzaN4evf9g==",
+      "version": "1.17.1",
+      "resolved": "https://registry.npmjs.org/@conform-to/dom/-/dom-1.17.1.tgz",
+      "integrity": "sha512-vpwCodVVWpQ6kbrlu5F85BC99ozDxqcrhmt+YDD81bCwvt6NtiycFID3NQQGQyn+bzmpb4qlF3Ay9YcljnrNHw==",
       "license": "MIT"
     },
     "node_modules/@conform-to/react": {
-      "version": "0.9.2",
-      "resolved": "https://registry.npmjs.org/@conform-to/react/-/react-0.9.2.tgz",
-      "integrity": "sha512-0eApSadAkM5/l1JNfQqpU+O/9lkjY89riG6jnrW8DWepyGfmN/COZtT7sRXla0SVOspXGJqGcKh+nk1f7Zbpaw==",
+      "version": "1.17.1",
+      "resolved": "https://registry.npmjs.org/@conform-to/react/-/react-1.17.1.tgz",
+      "integrity": "sha512-AXj6HMiG0e6mJXzVNDmeQ9FH4LbGA4HdSt+a0Yb09kEnpESkK3zCopFb8RkO8kls4XMQO05KAmaE6KDlhSzprQ==",
       "license": "MIT",
       "dependencies": {
-        "@conform-to/dom": "0.9.2"
+        "@conform-to/dom": "1.17.1"
       },
       "peerDependencies": {
-        "react": ">=16.8"
+        "react": ">=18"
       }
     },
     "node_modules/@conform-to/zod": {
-      "version": "0.9.2",
-      "resolved": "https://registry.npmjs.org/@conform-to/zod/-/zod-0.9.2.tgz",
-      "integrity": "sha512-treG9ZcuNuRERQ1uYvJSWT0zZuqHnYTzRwucg20+/WdjgKNSb60Br+Cy6BAHvVQ8dN6wJsGkHenkX2mSVw3xOA==",
+      "version": "1.17.1",
+      "resolved": "https://registry.npmjs.org/@conform-to/zod/-/zod-1.17.1.tgz",
+      "integrity": "sha512-oFt2OdCrAhNEKjjyc8QAgiykDI9s+RG9nAuxrqGyp/BFXuRPPiu0e+QIVUAxSnWtZ82swtSaf87DI+jTAyhaLg==",
       "license": "MIT",
+      "dependencies": {
+        "@conform-to/dom": "1.17.1"
+      },
       "peerDependencies": {
-        "@conform-to/dom": "0.9.2",
-        "zod": "^3.21.0"
+        "zod": "^3.21.0 || ^4.0.0"
       }
     },
     "node_modules/@csstools/color-helpers": {
@@ -30174,24 +30176,24 @@
       "license": "Unlicense"
     },
     "node_modules/zod": {
-      "version": "3.25.76",
-      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
-      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "version": "4.3.6",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-4.3.6.tgz",
+      "integrity": "sha512-rftlrkhHZOcjDwkGlnUtZZkvaPHCsDATp4pGpuOOMDaTdDDXF91wuVDJoWoPsKX/3YPQ5fHuF3STjcYyKr+Qhg==",
       "license": "MIT",
       "funding": {
         "url": "https://github.com/sponsors/colinhacks"
       }
     },
     "node_modules/zod-form-data": {
-      "version": "2.0.8",
-      "resolved": "https://registry.npmjs.org/zod-form-data/-/zod-form-data-2.0.8.tgz",
-      "integrity": "sha512-X31GkEc8uk5/L387L4TVI1z7obBbN/0MRHBHfHW3uMOWkVJeSsa+grvkTvY9qyFbNshKEnqK+jLJNlY+d7jpLw==",
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/zod-form-data/-/zod-form-data-3.0.1.tgz",
+      "integrity": "sha512-uwSrDzpLDoXeAxePjPHrjjMelE5pk5zL5JcwLFISvqidGjtPl7hcheH584xGcS76c9IRHq6tqdGkf+A4eKO6Cw==",
       "license": "MIT",
       "dependencies": {
         "@rvf/set-get": "^7.0.0"
       },
       "peerDependencies": {
-        "zod": ">= 3.11.0"
+        "zod": ">= 3.25.0"
       }
     },
     "node_modules/zwitch": {
diff --git a/package.json b/package.json
index 3569189c6..b9d248ace 100644
--- a/package.json
+++ b/package.json
@@ -31,8 +31,8 @@
   "dependencies": {
     "@aws-sdk/client-s3": "^3.971.0",
     "@aws-sdk/s3-request-presigner": "^3.971.0",
-    "@conform-to/react": "^0.9.2",
-    "@conform-to/zod": "^0.9.2",
+    "@conform-to/react": "^1.17.1",
+    "@conform-to/zod": "^1.17.1",
     "@directus/sdk": "^19.1.0",
     "@formatjs/intl": "^4.1.2",
     "@heroicons/react": "^2.2.0",
@@ -151,8 +151,8 @@
     "uuid": "^11.1.0",
     "vaul": "^1.1.2",
     "vite-plugin-markdown": "^2.2.0",
-    "zod": "^3.25.67",
-    "zod-form-data": "^2.0.8"
+    "zod": "^4.3.6",
+    "zod-form-data": "^3.0.1"
   },
   "devDependencies": {
     "@epic-web/config": "^1.21.0",