diff --git a/source/java/org/alfresco/rest/api/impl/NodesImpl.java b/source/java/org/alfresco/rest/api/impl/NodesImpl.java
index 9b92d51d3e..00086d1a5a 100644
--- a/source/java/org/alfresco/rest/api/impl/NodesImpl.java
+++ b/source/java/org/alfresco/rest/api/impl/NodesImpl.java
@@ -884,7 +884,6 @@ public class NodesImpl implements Nodes
 
     public Node updateNode(String nodeId, Node nodeInfo, Parameters parameters)
     {
-
         final NodeRef nodeRef = validateNode(nodeId);
 
         final Set<QName> fileOrFolder = new HashSet<>(Arrays.asList(ContentModel.TYPE_FOLDER, ContentModel.TYPE_CONTENT));
@@ -911,6 +910,61 @@ public class NodesImpl implements Nodes
             props.put(ContentModel.PROP_NAME, name);
         }
 
+        List<String> aspectNames = nodeInfo.getAspectNames();
+        if (aspectNames != null)
+        {
+            // note: can be empty (eg. to remove existing aspects (+ aspect properties) ... apart from cm:auditable, sys:referencable, sys:localized)
+            Set<QName> aspectQNames = new HashSet<>(aspectNames.size());
+            for (String aspectName : aspectNames)
+            {
+                QName aspectQName = QName.createQName(aspectName, namespaceService);
+                aspectQNames.add(aspectQName);
+            }
+
+            Set<QName> existingAspects = nodeService.getAspects(nodeRef);
+
+            Set<QName> aspectsToAdd = new HashSet<>(3);
+            Set<QName> aspectsToRemove = new HashSet<>(3);
+
+            for (QName aspectQName : aspectQNames)
+            {
+                if (EXCLUDED_ASPECTS.contains(aspectQName) || aspectQName.equals(ContentModel.ASPECT_AUDITABLE))
+                {
+                    continue; // ignore
+                }
+
+                if (! existingAspects.contains(aspectQName))
+                {
+                    aspectsToAdd.add(aspectQName);
+                }
+            }
+
+            for (QName existingAspect : existingAspects)
+            {
+                if (EXCLUDED_ASPECTS.contains(existingAspect) || existingAspect.equals(ContentModel.ASPECT_AUDITABLE))
+                {
+                    continue; // ignore
+                }
+
+                if (! aspectQNames.contains(existingAspect))
+                {
+                    aspectsToRemove.add(existingAspect);
+                }
+            }
+
+            // Note: for now, if aspectNames are sent then all that are required should be sent (to avoid properties from other existing aspects being removed)
+            // TODO: optional PATCH mechanism to add one new new aspect (with some related aspect properties) without affecting existing aspects/properties
+            for (QName aQName : aspectsToRemove)
+            {
+                nodeService.removeAspect(nodeRef, aQName);
+            }
+
+            for (QName aQName : aspectsToAdd)
+            {
+                nodeService.addAspect(nodeRef, aQName, null);
+            }
+        }
+
         if (props.size() > 0)
         {
             nodeService.addProperties(nodeRef, props);
diff --git a/source/java/org/alfresco/rest/api/model/Node.java b/source/java/org/alfresco/rest/api/model/Node.java
index bd3a74be81..265755805a 100644
--- a/source/java/org/alfresco/rest/api/model/Node.java
+++ b/source/java/org/alfresco/rest/api/model/Node.java
@@ -114,7 +114,7 @@ public class Node implements Comparable<Node>
     public static UserInfo lookupUserInfo(String userName, Map<String, UserInfo> mapUserInfo, PersonService personService) {
 
         UserInfo userInfo = mapUserInfo.get(userName);
-        if (userInfo == null)
+        if ((userInfo == null) && (userName != null))
         {
             String sysUserName = AuthenticationUtil.getSystemUserName();
             if (userName.equals(sysUserName) || (AuthenticationUtil.isMtEnabled() && userName.startsWith(sysUserName + "@")))