diff --git a/env/server.ts b/env/server.ts
index 24b5b0898..751143e62 100644
--- a/env/server.ts
+++ b/env/server.ts
@@ -65,7 +65,12 @@ export const env = createEnv({
     GOOGLE_STATIC_MAP_SIGNATURE_SECRET: z.string(),
     GOOGLE_DYNAMIC_MAP_ID: z.string(),
     GOOGLE_STATIC_MAP_ID: z.string(),
-    HIDE_FOR_NEXT_RELEASE: z.string(),
+    HIDE_FOR_NEXT_RELEASE: z
+      .string()
+      // only allow "true" or "false"
+      .refine((s) => s === "true" || s === "false")
+      // transform to boolean
+      .transform((s) => s === "true"),
   },
   emptyStringAsUndefined: true,
   runtimeEnv: {