diff --git a/src/Model/Fields/Payer/IP.php b/src/Model/Fields/Payer/IP.php
index eab1e0f..f1409bb 100644
--- a/src/Model/Fields/Payer/IP.php
+++ b/src/Model/Fields/Payer/IP.php
@@ -12,13 +12,12 @@ class IP extends Field
 {
     protected $name = __CLASS__;
     protected $type = self::STRING;
-    protected $minLength = 3;
     protected $maxLength = 255;
 
     protected function initValidators()
     {
         $this->addValidator(function ($value) {
-            if (false === filter_var($value, FILTER_VALIDATE_IP)) {
+            if (!empty($value) && false === filter_var($value, FILTER_VALIDATE_IP)) {
                 return new FieldValidationResult(false, 'Invalid IP address.');
             }
 
diff --git a/tests/Model/Fields/Payer/IpTest.php b/tests/Model/Fields/Payer/IpTest.php
index e36f3db..b938a6c 100644
--- a/tests/Model/Fields/Payer/IpTest.php
+++ b/tests/Model/Fields/Payer/IpTest.php
@@ -13,7 +13,7 @@ public function testIpv4()
         $ip = new Ip();
         $ip->setValue('127.0.0.1');
 
-        $this->assertEquals('127.0.0.1', $ip->getValue());
+        $this->assertSame('127.0.0.1', $ip->getValue());
     }
 
     public function testIpv6()
@@ -21,28 +21,33 @@ public function testIpv6()
         $ip = new Ip();
         $ip->setValue('2001:db8::1');
 
-        $this->assertEquals('2001:db8::1', $ip->getValue());
+        $this->assertSame('2001:db8::1', $ip->getValue());
     }
 
-    public function testInvalidIp()
+    public function testEmptyString()
     {
         $ip = new Ip();
+        $ip->setValue('');
 
-        $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Validation failed for field Tpay\OpenApi\Model\Fields\Payer\IP: Invalid IP address.');
-
-        $ip->setValue('TEST123');
+        $this->assertSame('', $ip->getValue());
     }
 
     public function testNull()
+    {
+        $ip = new Ip();
+        $ip->setValue(null);
+
+        $this->assertSame(null, $ip->getValue());
+    }
+
+    public function testInvalidIp()
     {
         $ip = new Ip();
 
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Value of field Tpay\OpenApi\Model\Fields\Payer\IP is too short. Min required 3');
         $this->expectExceptionMessage('Validation failed for field Tpay\OpenApi\Model\Fields\Payer\IP: Invalid IP address.');
 
-        $ip->setValue(null);
+        $ip->setValue('TEST123');
     }
 
     public function testWrongType()