diff --git a/idioms-xml-from-2.0/141-TLP-marking-structures.xml b/idioms-xml-from-2.0/141-TLP-marking-structures.xml
index 9510297..5c4e288 100644
--- a/idioms-xml-from-2.0/141-TLP-marking-structures.xml
+++ b/idioms-xml-from-2.0/141-TLP-marking-structures.xml
@@ -27,7 +27,7 @@
             </indicator:Valid_Time_Position>
             <indicator:Observable id="example:Observable-5d62a5b7-d532-44e8-ab7e-e4ae4f63bb00">
                 <cybox:Object id="example:URI-092d0753-2cb1-4370-852f-c3152612ee72">
-                    <cybox:Properties xsi:type="URIObj:URIObjectType">
+                    <cybox:Properties xsi:type="URIObj:URIObjectType" type="URL" >
                         <URIObj:Value condition="Equals">http://x4z9arb.cn/4712</URIObj:Value>
                     </cybox:Properties>
                 </cybox:Object>
diff --git a/idioms-xml-from-2.0/issue-35.xml b/idioms-xml-from-2.0/issue-35.xml
index 8d17b9d..bc42bf1 100755
--- a/idioms-xml-from-2.0/issue-35.xml
+++ b/idioms-xml-from-2.0/issue-35.xml
@@ -23,7 +23,7 @@
             </indicator:Valid_Time_Position>
             <indicator:Observable id="example:Observable-2715bd96-3b1f-417e-9992-e0196f014a03">
                 <cybox:Object id="example:URI-92ddbea5-12e7-487c-b3a5-18cd1a7442b4">
-                    <cybox:Properties xsi:type="URIObj:URIObjectType">
+                    <cybox:Properties xsi:type="URIObj:URIObjectType" type="URL">
                         <URIObj:Value condition="Equals">http://writerbliss.com/Payments/</URIObj:Value>
                     </cybox:Properties>
                 </cybox:Object>
diff --git a/idioms-xml-from-2.1/141-TLP-marking-structures.xml b/idioms-xml-from-2.1/141-TLP-marking-structures.xml
index 29b327f..ff67506 100644
--- a/idioms-xml-from-2.1/141-TLP-marking-structures.xml
+++ b/idioms-xml-from-2.1/141-TLP-marking-structures.xml
@@ -27,7 +27,7 @@
             </indicator:Valid_Time_Position>
             <indicator:Observable id="example:Observable-1ac6a0a4-9097-4c72-8862-aae449ddbef8">
                 <cybox:Object id="example:URI-153178c1-2ffe-4bfe-abea-5795c185f01f">
-                    <cybox:Properties xsi:type="URIObj:URIObjectType">
+                    <cybox:Properties xsi:type="URIObj:URIObjectType" type="URL">
                         <URIObj:Value condition="Equals">http://x4z9arb.cn/4712</URIObj:Value>
                     </cybox:Properties>
                 </cybox:Object>
diff --git a/idioms-xml-from-2.1/issue-35.xml b/idioms-xml-from-2.1/issue-35.xml
index 9bd2e89..2ce9c7d 100755
--- a/idioms-xml-from-2.1/issue-35.xml
+++ b/idioms-xml-from-2.1/issue-35.xml
@@ -23,7 +23,7 @@
             </indicator:Valid_Time_Position>
             <indicator:Observable id="example:Observable-2715bd96-3b1f-417e-9992-e0196f014a03">
                 <cybox:Object id="example:URI-92ddbea5-12e7-487c-b3a5-18cd1a7442b4">
-                    <cybox:Properties xsi:type="URIObj:URIObjectType">
+                    <cybox:Properties xsi:type="URIObj:URIObjectType" type="URL">
                         <URIObj:Value condition="Equals">http://writerbliss.com/Payments/</URIObj:Value>
                     </cybox:Properties>
                 </cybox:Object>
diff --git a/setup.cfg b/setup.cfg
index 44e0ed9..180e88e 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 1.0.1
+current_version = 4.0.1
 commit = True
 tag = True
 
diff --git a/stix2slider/convert_pattern.py b/stix2slider/convert_pattern.py
index 1e56bb0..5920190 100755
--- a/stix2slider/convert_pattern.py
+++ b/stix2slider/convert_pattern.py
@@ -812,7 +812,8 @@ def convert_url_pattern(exp2x, obj1x, id2x):
         convert_operator(exp2x.operator, obj1x.value, id2x)
     else:
         warn("%s is an illegal or custom property in the pattern of %s, which is not handled, yet", 614, prop_name, id2x)
-
+    # add a type property in cybox field
+    obj1x.type_ = "URL"
 
 def convert_mutex_pattern(exp2x, obj1x, id2x):
     prop_name = exp2x.lhs.property_path[0].property_name
diff --git a/stix2slider/version.py b/stix2slider/version.py
index ce1305b..76ad18b 100755
--- a/stix2slider/version.py
+++ b/stix2slider/version.py
@@ -1 +1 @@
-__version__ = "4.0.0"
+__version__ = "4.0.1"