diff --git a/inc/caldav-PROPPATCH.php b/inc/caldav-PROPPATCH.php
index d8951a32..6de065bb 100644
--- a/inc/caldav-PROPPATCH.php
+++ b/inc/caldav-PROPPATCH.php
@@ -57,13 +57,13 @@ foreach( $setprops AS $k => $setting ) {
       * Can't set displayname on resources - only collections or principals
       */
       if ( $request->IsCollection() || $request->IsPrincipal() ) {
-        if ( $request->IsCollection() ) {
-          $sql .= sprintf( "UPDATE collection SET dav_displayname = %s, modified = current_timestamp WHERE dav_name = %s;",
-                                            qpg($content), qpg($request->path) );
+        if ( $request->IsPrincipal() ) {
+          $sql .= sprintf( "UPDATE dav_principal SET fullname = %s, displayname = %s, modified = current_timestamp WHERE user_no = %s;",
+                                            qpg($content), qpg($content), $request->user_no );
         }
         else {
-          $sql .= sprintf( "UPDATE usr SET fullname = %s, updated = current_timestamp WHERE user_no = %s;",
-                                            qpg($content), $request->user_no );
+          $sql .= sprintf( "UPDATE collection SET dav_displayname = %s, modified = current_timestamp WHERE dav_name = %s;",
+                                            qpg($content), qpg($request->path) );
         }
         $success[$tag] = 1;
       }
diff --git a/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.result b/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.result
new file mode 100644
index 00000000..41ebb735
--- /dev/null
+++ b/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.result
@@ -0,0 +1,27 @@
+HTTP/1.1 200 OK
+Date: Dow, 01 Jan 2000 00:00:00 GMT
+DAV: 1, 2, access-control, calendar-access, calendar-schedule, extended-mkcol, calendar-proxy
+Content-Length: 219
+Content-Type: text/xml; charset="utf-8"
+
+<?xml version="1.0" encoding="utf-8" ?>
+<multistatus xmlns="DAV:">
+ <response>
+  <href>/caldav.php/user1/</href>
+  <responsedescription>All requested changes were made.</responsedescription>
+ </response>
+</multistatus>
+
+      displayname: >User Number One PROPPATCH'd in<
+         fullname: >User Number One PROPPATCH'd in<
+
+       changed_by: >10<
+         dav_name: >/user1/<
+    property_name: >http://dotcal.com/principal-properties:country<
+   property_value: >New Zealand<
+
+       changed_by: >10<
+         dav_name: >/user1/<
+    property_name: >http://dotcal.com/principal-properties:countrycode<
+   property_value: >NZ<
+
diff --git a/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.test b/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.test
new file mode 100644
index 00000000..cd6584cb
--- /dev/null
+++ b/testing/tests/regression-suite/844-Spec-PROPPATCH-principal.test
@@ -0,0 +1,31 @@
+#
+# Check for support of PROPPATCH method
+#
+# An attempt to set an arbitrary property on a principal
+#
+TYPE=PROPPATCH
+URL=http://mycaldav/caldav.php/user1/
+HEADER=User-agent: SpecTest PROPPATCH
+HEADER=Content-type: text/xml
+HEAD
+
+BEGINDATA
+<?xml version="1.0" encoding="utf-8" ?> 
+<propertyupdate xmlns="DAV:" xmlns:DC="http://dotcal.com/principal-properties"> 
+  <set> 
+    <prop> 
+      <DC:country>New Zealand</DC:country> 
+      <DC:countrycode>NZ</DC:countrycode> 
+      <displayname>User Number One PROPPATCH'd in</displayname> 
+    </prop> 
+  </set> 
+</propertyupdate>
+ENDDATA
+
+QUERY
+SELECT fullname, displayname FROM dav_principal WHERE dav_name = '/user1/';
+ENDQUERY
+
+QUERY
+SELECT dav_name, property_name, property_value, changed_by FROM property WHERE dav_name = '/user1/';
+ENDQUERY
diff --git a/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.result b/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.result
new file mode 100644
index 00000000..2ad29cd9
--- /dev/null
+++ b/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.result
@@ -0,0 +1,17 @@
+HTTP/1.1 200 OK
+Date: Dow, 01 Jan 2000 00:00:00 GMT
+DAV: 1, 2, access-control, calendar-access, calendar-schedule, extended-mkcol, calendar-proxy
+Content-Length: 219
+Content-Type: text/xml; charset="utf-8"
+
+<?xml version="1.0" encoding="utf-8" ?>
+<multistatus xmlns="DAV:">
+ <response>
+  <href>/caldav.php/user1/</href>
+  <responsedescription>All requested changes were made.</responsedescription>
+ </response>
+</multistatus>
+
+      displayname: >User 1<
+         fullname: >User 1<
+
diff --git a/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.test b/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.test
new file mode 100644
index 00000000..b08d5d01
--- /dev/null
+++ b/testing/tests/regression-suite/845-Spec-PROPPATCH-principal.test
@@ -0,0 +1,35 @@
+#
+# Check for support of PROPPATCH method
+#
+# An attempt to set an arbitrary property on a principal
+#
+TYPE=PROPPATCH
+URL=http://mycaldav/caldav.php/user1/
+HEADER=User-agent: SpecTest PROPPATCH
+HEADER=Content-type: text/xml
+HEAD
+
+BEGINDATA
+<?xml version="1.0" encoding="utf-8" ?> 
+<propertyupdate xmlns="DAV:" xmlns:DC="http://dotcal.com/principal-properties"> 
+  <set> 
+    <prop> 
+      <displayname>User 1</displayname> 
+    </prop> 
+  </set> 
+  <remove> 
+    <prop> 
+      <DC:country/>
+      <DC:countrycode/>
+    </prop> 
+  </remove> 
+</propertyupdate>
+ENDDATA
+
+QUERY
+SELECT fullname, displayname FROM dav_principal WHERE dav_name = '/user1/';
+ENDQUERY
+
+QUERY
+SELECT * FROM property WHERE dav_name = '/user1/';
+ENDQUERY