diff --git a/radicale/app/propfind.py b/radicale/app/propfind.py
index 52d0b00..a40ea3a 100644
--- a/radicale/app/propfind.py
+++ b/radicale/app/propfind.py
@@ -85,7 +85,7 @@ def xml_propfind_response(
 
     if isinstance(item, storage.BaseCollection):
         is_collection = True
-        is_leaf = item.tag in ("VADDRESSBOOK", "VCALENDAR")
+        is_leaf = item.tag in ("VADDRESSBOOK", "VCALENDAR", "VSUBSCRIBED")
         collection = item
         # Some clients expect collections to end with `/`
         uri = pathutils.unstrip_path(item.path, True)
@@ -259,6 +259,10 @@ def xml_propfind_response(
                         child_element = ET.Element(
                             xmlutils.make_clark("C:calendar"))
                         element.append(child_element)
+                    elif item.get_meta("tag") == "VSUBSCRIBED":
+                        child_element = ET.Element(
+                            xmlutils.make_clark("CS:subscribed"))
+                        element.append(child_element)
                 child_element = ET.Element(xmlutils.make_clark("D:collection"))
                 element.append(child_element)
             elif tag == xmlutils.make_clark("RADICALE:displayname"):
@@ -286,6 +290,14 @@ def xml_propfind_response(
                     element.text, _ = collection.sync()
                 else:
                     is404 = True
+            elif tag == xmlutils.make_clark("CS:source"):
+                if is_leaf:
+                    child_element = ET.Element(xmlutils.make_clark("D:href"))
+                    child_element.text = item.get_meta('CS:source')
+                    element.append(child_element)
+                else:
+                    is404 = True
+                        
             else:
                 human_tag = xmlutils.make_human_tag(tag)
                 tag_text = collection.get_meta(human_tag)
diff --git a/radicale/item/__init__.py b/radicale/item/__init__.py
index 04362b7..6adb139 100644
--- a/radicale/item/__init__.py
+++ b/radicale/item/__init__.py
@@ -91,7 +91,7 @@ def check_and_sanitize_items(
     The ``tag`` of the collection.
 
     """
-    if tag and tag not in ("VCALENDAR", "VADDRESSBOOK"):
+    if tag and tag not in ("VCALENDAR", "VADDRESSBOOK", "VSUBSCRIBED"):
         raise ValueError("Unsupported collection tag: %r" % tag)
     if not is_collection and len(vobject_items) != 1:
         raise ValueError("Item contains %d components" % len(vobject_items))
@@ -230,7 +230,7 @@ def check_and_sanitize_props(props: MutableMapping[Any, Any]
             raise ValueError("Value of %r must be %r not %r: %r" % (
                 k, str.__name__, type(v).__name__, v))
         if k == "tag":
-            if v not in ("", "VCALENDAR", "VADDRESSBOOK"):
+            if v not in ("", "VCALENDAR", "VADDRESSBOOK", "VSUBSCRIBED"):
                 raise ValueError("Unsupported collection tag: %r" % v)
     return props
 
diff --git a/radicale/xmlutils.py b/radicale/xmlutils.py
index 09508d9..da59c08 100644
--- a/radicale/xmlutils.py
+++ b/radicale/xmlutils.py
@@ -33,7 +33,8 @@ from radicale import item, pathutils
 
 MIMETYPES: Mapping[str, str] = {
     "VADDRESSBOOK": "text/vcard",
-    "VCALENDAR": "text/calendar"}
+    "VCALENDAR": "text/calendar",
+    "VSUBSCRIBED": "text/calendar"}
 
 OBJECT_MIMETYPES: Mapping[str, str] = {
     "VCARD": "text/vcard",