diff --git a/src/Core/Concerns/SdkPage.php b/src/Core/Concerns/SdkPage.php
index 96e2aa54..0f4d40da 100644
--- a/src/Core/Concerns/SdkPage.php
+++ b/src/Core/Concerns/SdkPage.php
@@ -57,7 +57,7 @@ public function hasNextPage(): bool
     public function getNextPage(): static
     {
         $next = $this->nextRequest();
-        if (!$next) {
+        if ($next === null) {
             throw new \RuntimeException(
                 'No next page expected; please check `.hasNextPage()` before calling `.getNextPage()`.'
             );
diff --git a/src/Documents/DocumentCreate/Item.php b/src/Documents/DocumentCreate/Item.php
index b9928793..784bd44d 100644
--- a/src/Documents/DocumentCreate/Item.php
+++ b/src/Documents/DocumentCreate/Item.php
@@ -16,7 +16,7 @@
  *   allowances?: list<Allowance>|null,
  *   amount?: float|string|null,
  *   charges?: list<Charge>|null,
- *   date?: null|null,
+ *   date?: \DateTimeInterface|null,
  *   description?: string|null,
  *   productCode?: string|null,
  *   quantity?: float|string|null,
@@ -53,9 +53,8 @@ final class Item implements BaseModel
     #[Api(list: Charge::class, nullable: true, optional: true)]
     public ?array $charges;
 
-    /** @var null|null $date */
     #[Api(nullable: true, optional: true)]
-    public null $date;
+    public ?\DateTimeInterface $date;
 
     /**
      * The description of the line item.
@@ -119,7 +118,7 @@ public static function with(
         ?array $allowances = null,
         float|string|null $amount = null,
         ?array $charges = null,
-        null $date = null,
+        ?\DateTimeInterface $date = null,
         ?string $description = null,
         ?string $productCode = null,
         float|string|null $quantity = null,
@@ -182,10 +181,7 @@ public function withCharges(?array $charges): self
         return $obj;
     }
 
-    /**
-     * @param null|null $date
-     */
-    public function withDate(null $date): self
+    public function withDate(?\DateTimeInterface $date): self
     {
         $obj = clone $this;
         $obj->date = $date;
diff --git a/src/Documents/DocumentCreateParams/Item.php b/src/Documents/DocumentCreateParams/Item.php
index 35efec77..b7fa5f4e 100644
--- a/src/Documents/DocumentCreateParams/Item.php
+++ b/src/Documents/DocumentCreateParams/Item.php
@@ -16,7 +16,7 @@
  *   allowances?: list<Allowance>|null,
  *   amount?: float|string|null,
  *   charges?: list<Charge>|null,
- *   date?: null|null,
+ *   date?: \DateTimeInterface|null,
  *   description?: string|null,
  *   productCode?: string|null,
  *   quantity?: float|string|null,
@@ -53,9 +53,8 @@ final class Item implements BaseModel
     #[Api(list: Charge::class, nullable: true, optional: true)]
     public ?array $charges;
 
-    /** @var null|null $date */
     #[Api(nullable: true, optional: true)]
-    public null $date;
+    public ?\DateTimeInterface $date;
 
     /**
      * The description of the line item.
@@ -119,7 +118,7 @@ public static function with(
         ?array $allowances = null,
         float|string|null $amount = null,
         ?array $charges = null,
-        null $date = null,
+        ?\DateTimeInterface $date = null,
         ?string $description = null,
         ?string $productCode = null,
         float|string|null $quantity = null,
@@ -182,10 +181,7 @@ public function withCharges(?array $charges): self
         return $obj;
     }
 
-    /**
-     * @param null|null $date
-     */
-    public function withDate(null $date): self
+    public function withDate(?\DateTimeInterface $date): self
     {
         $obj = clone $this;
         $obj->date = $date;
diff --git a/src/Documents/DocumentNewFromPdfResponse/Item.php b/src/Documents/DocumentNewFromPdfResponse/Item.php
index 92344683..c4cab023 100644
--- a/src/Documents/DocumentNewFromPdfResponse/Item.php
+++ b/src/Documents/DocumentNewFromPdfResponse/Item.php
@@ -16,7 +16,7 @@
  *   allowances?: list<Allowance>|null,
  *   amount?: string|null,
  *   charges?: list<Charge>|null,
- *   date?: null|null,
+ *   date?: \DateTimeInterface|null,
  *   description?: string|null,
  *   productCode?: string|null,
  *   quantity?: string|null,
@@ -53,9 +53,8 @@ final class Item implements BaseModel
     #[Api(list: Charge::class, nullable: true, optional: true)]
     public ?array $charges;
 
-    /** @var null|null $date */
     #[Api(nullable: true, optional: true)]
-    public null $date;
+    public ?\DateTimeInterface $date;
 
     /**
      * The description of the line item.
@@ -119,7 +118,7 @@ public static function with(
         ?array $allowances = null,
         ?string $amount = null,
         ?array $charges = null,
-        null $date = null,
+        ?\DateTimeInterface $date = null,
         ?string $description = null,
         ?string $productCode = null,
         ?string $quantity = null,
@@ -182,10 +181,7 @@ public function withCharges(?array $charges): self
         return $obj;
     }
 
-    /**
-     * @param null|null $date
-     */
-    public function withDate(null $date): self
+    public function withDate(?\DateTimeInterface $date): self
     {
         $obj = clone $this;
         $obj->date = $date;
diff --git a/src/Documents/DocumentResponse/Item.php b/src/Documents/DocumentResponse/Item.php
index 32fb1ece..ad7d627b 100644
--- a/src/Documents/DocumentResponse/Item.php
+++ b/src/Documents/DocumentResponse/Item.php
@@ -16,7 +16,7 @@
  *   allowances?: list<Allowance>|null,
  *   amount?: string|null,
  *   charges?: list<Charge>|null,
- *   date?: null|null,
+ *   date?: \DateTimeInterface|null,
  *   description?: string|null,
  *   productCode?: string|null,
  *   quantity?: string|null,
@@ -53,9 +53,8 @@ final class Item implements BaseModel
     #[Api(list: Charge::class, nullable: true, optional: true)]
     public ?array $charges;
 
-    /** @var null|null $date */
     #[Api(nullable: true, optional: true)]
-    public null $date;
+    public ?\DateTimeInterface $date;
 
     /**
      * The description of the line item.
@@ -119,7 +118,7 @@ public static function with(
         ?array $allowances = null,
         ?string $amount = null,
         ?array $charges = null,
-        null $date = null,
+        ?\DateTimeInterface $date = null,
         ?string $description = null,
         ?string $productCode = null,
         ?string $quantity = null,
@@ -182,10 +181,7 @@ public function withCharges(?array $charges): self
         return $obj;
     }
 
-    /**
-     * @param null|null $date
-     */
-    public function withDate(null $date): self
+    public function withDate(?\DateTimeInterface $date): self
     {
         $obj = clone $this;
         $obj->date = $date;
diff --git a/src/DocumentsNumberPage.php b/src/DocumentsNumberPage.php
index 381a918e..3bf10853 100644
--- a/src/DocumentsNumberPage.php
+++ b/src/DocumentsNumberPage.php
@@ -111,7 +111,21 @@ public function getItems(): array
     public function nextRequest(): ?array
     {
         $currentPage = $this->page ?? 1;
+        $pageSize = $this->pageSize ?? 0;
+        $total = $this->total ?? 0;
+
+        // Check if there are more pages
+        if ($pageSize === 0 || $total === 0) {
+            return null;
+        }
+
+        $totalPages = (int) ceil($total / $pageSize);
+        if ($currentPage >= $totalPages) {
+            return null;
+        }
+
         $nextRequest = $this->request;
+        $nextRequest['query']['page'] = $currentPage + 1;
 
         return [$nextRequest, $this->options];
     }
diff --git a/src/DocumentsNumberPage/Item.php b/src/DocumentsNumberPage/Item.php
index 7ca75a74..bcabfe05 100644
--- a/src/DocumentsNumberPage/Item.php
+++ b/src/DocumentsNumberPage/Item.php
@@ -8,7 +8,7 @@
 use EInvoiceAPI\Core\Contracts\BaseModel;
 
 /**
- * @phpstan-type ItemShape = array{}
+ * @phpstan-type ItemShape = array<string, mixed>
  */
 final class Item implements BaseModel
 {
diff --git a/src/Validate/ValidateValidateJsonParams/Item.php b/src/Validate/ValidateValidateJsonParams/Item.php
index e43054d9..d014e9c6 100644
--- a/src/Validate/ValidateValidateJsonParams/Item.php
+++ b/src/Validate/ValidateValidateJsonParams/Item.php
@@ -16,7 +16,7 @@
  *   allowances?: list<Allowance>|null,
  *   amount?: float|string|null,
  *   charges?: list<Charge>|null,
- *   date?: null|null,
+ *   date?: \DateTimeInterface|null,
  *   description?: string|null,
  *   productCode?: string|null,
  *   quantity?: float|string|null,
@@ -53,9 +53,8 @@ final class Item implements BaseModel
     #[Api(list: Charge::class, nullable: true, optional: true)]
     public ?array $charges;
 
-    /** @var null|null $date */
     #[Api(nullable: true, optional: true)]
-    public null $date;
+    public ?\DateTimeInterface $date;
 
     /**
      * The description of the line item.
@@ -119,7 +118,7 @@ public static function with(
         ?array $allowances = null,
         float|string|null $amount = null,
         ?array $charges = null,
-        null $date = null,
+        ?\DateTimeInterface $date = null,
         ?string $description = null,
         ?string $productCode = null,
         float|string|null $quantity = null,
@@ -182,10 +181,7 @@ public function withCharges(?array $charges): self
         return $obj;
     }
 
-    /**
-     * @param null|null $date
-     */
-    public function withDate(null $date): self
+    public function withDate(?\DateTimeInterface $date): self
     {
         $obj = clone $this;
         $obj->date = $date;