diff --git a/CHANGELOG.md b/CHANGELOG.md
index 06dd9fcb..5f5e9a06 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Clixon Changelog
 
-## 4.2.0 (Expected: September)
+## 4.2.0 (Expected: October)
 
 ### Major New features
 * Backend daemon can drop privileges after initialization to run as non-privileged user
@@ -10,17 +10,15 @@
   * If dropped temporary, you can restore privileges with `restore_priv()`
 
 ### API changes on existing features (you may need to change your code)
+* Stricter handling of multi-namespace handling
+  * This occurs in cases where there are more than one XML namespaces in a config tree, such as `augment`:ed trees.
+  * Affects all parts of the system, including datastore, backend, restconf and cli.
+  * Examples of a mandated stricter usage of a simple augment `b` of symbol `a`. Assume `a` is in module `mod1` with namespace `urn:example:a` and `b` is in module `mod2` with namespace `urn:example:b`:
+    * RESTCONF: `GET http://localhost/restconf/data/mod1:a/mod2:b`
+    * NETCONF: `<a xmlns="urn:example:a" xmlns:b="urn:example:b"><b:b>42</b:b></a>`
+    * XPATH (in edit-config filter): `<filter type="xpath" select="a:a/b:b" xmlns:a="urn:example:a" xmlns:b="urn:example:b"/>`
 * RESTCONF error reporting
-  * Invalid api-path syntax (eg non-matching yang) error changed from 412 operation-failed to 400 unknown-element / invalid-value. For example, change from
-    ```
-    HTTP/1.1 412 Precondition Failed
-    {"ietf-restconf:errors":{"error":{"error-type":"protocol","error-tag":"operation-failed","error-severity":"error","error-message":"No such yang module: badmodule"}}}
-    ```
-    to:
-    ```
-    HTTP/1.1 400 Bad Request
-    {"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"invalid-value","error-severity":"error","error-message":"No such yang module: badmodule"}}}
-    ```    
+  * Invalid api-path syntax (eg non-matching yang) error changed from 412 operation-failed to 400 Bad request invalid-value, or unknown-element.
 * Typical installation should now add a `clicon` user (as well as group)
 * New clixon-config@2019-09-11.yang revision
   * Added: CLICON_BACKEND_USER: drop of privileges to user,
@@ -33,6 +31,7 @@
 * Configure and test modification for better Freebsd port
 	
 ### Corrected Bugs
+* See "Stricter handling of multi-namespace handling" in API-changes above.
 * Hello netconf candidate capability misspelled, mentioned in [Can clixon_netconf receive netconf packets as a server? #93](https://github.com/clicon/clixon/issues/93)
 * [Cannot write to config using restconf example #91](https://github.com/clicon/clixon/issues/91)
   * Updated restconf documentation (the example was wrong)
diff --git a/apps/backend/backend_client.c b/apps/backend/backend_client.c
index bbdb0b54..385ca4de 100644
--- a/apps/backend/backend_client.c
+++ b/apps/backend/backend_client.c
@@ -527,11 +527,10 @@ from_client_edit_config(clicon_handle h,
 	if (xml_spec(xc) != NULL)
 	    xml_spec_set(xc, NULL);
 	/* Populate XML with Yang spec (why not do this in parser?) 
-	 * Maybe validate xml here as in text_modify_top?
 	 */
 	if (xml_apply(xc, CX_ELMNT, xml_spec_populate, yspec) < 0)
 	    goto done;
-
+	/* Maybe validate xml here as in text_modify_top? */
 	if (xml_apply(xc, CX_ELMNT, xml_non_config_data, &non_config) < 0)
 	    goto done;
 	if (non_config){
diff --git a/apps/backend/backend_commit.c b/apps/backend/backend_commit.c
index 3c115532..d67f1490 100644
--- a/apps/backend/backend_commit.c
+++ b/apps/backend/backend_commit.c
@@ -195,10 +195,12 @@ startup_common(clicon_handle       h,
 	goto ok;
     }
     if (msd){
+	/* Here xt is old syntax */
 	if ((ret = clixon_module_upgrade(h, xt, msd, cbret)) < 0)
 	    goto done;
 	if (ret == 0)
 	    goto fail;
+	/* Here xt is new syntax */
     }
     if ((yspec = clicon_dbspec_yang(h)) == NULL){
 	clicon_err(OE_YANG, 0, "Yang spec not set");
diff --git a/apps/backend/backend_startup.c b/apps/backend/backend_startup.c
index 35204067..96f35baa 100644
--- a/apps/backend/backend_startup.c
+++ b/apps/backend/backend_startup.c
@@ -70,7 +70,6 @@
 #include "backend_commit.h"
 #include "backend_startup.h"
 
-
 /*! Merge db1 into db2 without commit 
  * @retval   -1       Error
  * @retval    0       Validation failed (with cbret set)
@@ -166,9 +165,10 @@ load_extraxml(clicon_handle h,
 	      const char   *db,
 	      cbuf         *cbret)
 {
-    int    retval =  -1;
-    cxobj *xt = NULL;
-    int    fd = -1;
+    int        retval =  -1;
+    cxobj     *xt = NULL;
+    int        fd = -1;
+    yang_stmt *yspec = NULL;
 
     if (filename == NULL)
 	return 1;
@@ -176,7 +176,8 @@ load_extraxml(clicon_handle h,
 	clicon_err(OE_UNIX, errno, "open(%s)", filename);
 	goto done;
     }
-    if (xml_parse_file(fd, "</config>", NULL, &xt) < 0)
+    yspec = clicon_dbspec_yang(h);
+    if (xml_parse_file(fd, "</config>", yspec, &xt) < 0)
 	goto done;
     /* Replace parent w first child */
     if (xml_rootchild(xt, 0, &xt) < 0)
diff --git a/apps/restconf/restconf_lib.c b/apps/restconf/restconf_lib.c
index 268974bb..17f45500 100644
--- a/apps/restconf/restconf_lib.c
+++ b/apps/restconf/restconf_lib.c
@@ -526,6 +526,7 @@ api_return_err(clicon_handle h,
 	    FCGX_FPrintF(r->out, "%s", cbuf_get(cb));
 	    FCGX_FPrintF(r->out, "}\r\n");
 	}
+	break;
     default:
 	clicon_err(OE_YANG, EINVAL, "Invalid media type %d", media);
 	goto done;
diff --git a/apps/restconf/restconf_methods_get.c b/apps/restconf/restconf_methods_get.c
index 8d8a72f6..1a9214dc 100644
--- a/apps/restconf/restconf_methods_get.c
+++ b/apps/restconf/restconf_methods_get.c
@@ -165,8 +165,16 @@ api_data_get2(clicon_handle h,
     if ((cbpath = cbuf_new()) == NULL)
         goto done;
     cprintf(cbpath, "/");
-    /* We know "data" is element pi-1 */
-    if ((ret = api_path2xpath_cvv(pcvec, pi, yspec, cbpath, &namespace, &xerr)) < 0)
+    /* Create a namespace context for ymod as the default namespace to use with
+     * xpath expressions */
+    if ((nsc = cvec_new(0)) == NULL){
+	clicon_err(OE_XML, errno, "cvec_new");
+	goto done;
+    }
+    /* We know "data" is element pi-1.
+     * Translate api-path to xpath: xpath (cbpath) and namespace context (nsc)
+     */
+    if ((ret = api_path2xpath_cvv2(pcvec, pi, yspec, cbpath, nsc, &xerr)) < 0)
 	goto done;
     if (ret == 0){
 	clicon_err_reset();
@@ -178,36 +186,17 @@ api_data_get2(clicon_handle h,
 	    goto done;
 	goto ok;
     }
-    if (ret == 0){
-	if (netconf_operation_failed_xml(&xerr, "protocol", clicon_err_reason) < 0)
-	    goto done;
-	clicon_err_reset();
-	if ((xe = xpath_first(xerr, "rpc-error")) == NULL){
-	    clicon_err(OE_XML, EINVAL, "rpc-error not found (internal error)");
-	    goto done;
-	}
-	if (api_return_err(h, r, xe, pretty, media_out, 0) < 0)
-	    goto done;
-	goto ok;
-    }
     xpath = cbuf_get(cbpath);
     clicon_debug(1, "%s path:%s", __FUNCTION__, xpath);
-    /* Create a namespace context for ymod as the default namespace to use with
-     * xpath expressions */
-    if ((nsc = xml_nsctx_init(NULL, namespace)) == NULL)
-	goto done;
     switch (content){
     case CONTENT_CONFIG:
-	ret = clicon_rpc_get(h, xpath, namespace, CONTENT_CONFIG, depth, &xret);
-	break;
     case CONTENT_NONCONFIG:
-	ret = clicon_rpc_get(h, xpath, namespace, CONTENT_NONCONFIG, depth, &xret);
-	break;
     case CONTENT_ALL:
-	ret = clicon_rpc_get(h, xpath, namespace, CONTENT_ALL, depth, &xret);
+	ret = clicon_rpc_get_nsc(h, xpath, nsc, content, depth, &xret);
 	break;
     default:
 	clicon_err(OE_XML, EINVAL, "Invalid content attribute %d", content);
+	goto done;
 	break;
     }
     if (ret < 0){
@@ -291,14 +280,14 @@ api_data_get2(clicon_handle h,
 	switch (media_out){
 	case YANG_DATA_XML:
 	    for (i=0; i<xlen; i++){
-		char *prefix, *namespace2; /* Same as namespace? */
+		char *prefix;
 		x = xvec[i];
 		/* Some complexities in grafting namespace in existing trees to new */
 		prefix = xml_prefix(x);
 		if (xml_find_type_value(x, prefix, "xmlns", CX_ATTR) == NULL){
-		    if (xml2ns(x, prefix, &namespace2) < 0)
+		    if (xml2ns(x, prefix, &namespace) < 0)
 			goto done;
-		    if (namespace2 && xmlns_set(x, prefix, namespace2) < 0)
+		    if (namespace && xmlns_set(x, prefix, namespace) < 0)
 			goto done;
 		}
 		if (clicon_xml2cbuf(cbx, x, 0, pretty, -1) < 0) /* Dont print top object?  */
diff --git a/lib/clixon/clixon_proto_client.h b/lib/clixon/clixon_proto_client.h
index 9bdbe204..8dfe0416 100644
--- a/lib/clixon/clixon_proto_client.h
+++ b/lib/clixon/clixon_proto_client.h
@@ -53,6 +53,7 @@ int clicon_rpc_delete_config(clicon_handle h, char *db);
 int clicon_rpc_lock(clicon_handle h, char *db);
 int clicon_rpc_unlock(clicon_handle h, char *db);
 int clicon_rpc_get(clicon_handle h, char *xpath, char *namespace, netconf_content content, int32_t depth, cxobj **xret);
+int clicon_rpc_get_nsc(clicon_handle h, char *xpath, cvec *nsc, netconf_content content, int32_t depth, cxobj **xret);
 int clicon_rpc_close_session(clicon_handle h);
 int clicon_rpc_kill_session(clicon_handle h, int session_id);
 int clicon_rpc_validate(clicon_handle h, char *db);
diff --git a/lib/clixon/clixon_xml.h b/lib/clixon/clixon_xml.h
index 9c961581..73d06f96 100644
--- a/lib/clixon/clixon_xml.h
+++ b/lib/clixon/clixon_xml.h
@@ -108,9 +108,17 @@ char     *xml_name(cxobj *xn);
 int       xml_name_set(cxobj *xn, char *name);
 char     *xml_prefix(cxobj *xn);
 int       xml_prefix_set(cxobj *xn, char *name);
+char     *nscache_get(cxobj *x, char *prefix);
+int       nscache_get_prefix(cxobj *x, char *namespace, char **prefix);
+cvec     *nscache_get_all(cxobj *x);
+int       nscache_set(cxobj *x,	char *prefix, char *namespace);
+
 int       nscache_clear(cxobj *x);
 int       nscache_replace(cxobj *x, cvec *ns);
+
 int       xml2ns(cxobj *x, char *localname, char **namespace);
+int       xml2prefix(cxobj *xn, char *namespace, char **prefixp);
+
 int       xmlns_set(cxobj *x, char *prefix, char *namespace);
 cxobj    *xml_parent(cxobj *xn);
 int       xml_parent_set(cxobj *xn, cxobj *parent);
diff --git a/lib/clixon/clixon_xml_map.h b/lib/clixon/clixon_xml_map.h
index c464ac8f..ee935154 100644
--- a/lib/clixon/clixon_xml_map.h
+++ b/lib/clixon/clixon_xml_map.h
@@ -71,6 +71,7 @@ int xml_non_config_data(cxobj *xt, void *arg);
 int xml_spec_populate_rpc(clicon_handle h, cxobj *x, yang_stmt *yspec);
 int xml_spec_populate(cxobj *x, void *arg);
 int api_path2xpath_cvv(cvec *api_path, int offset, yang_stmt *yspec, cbuf *xpath, char **namespace, cxobj **xerr);
+int api_path2xpath_cvv2(cvec *api_path, int offset, yang_stmt *yspec, cbuf *xpath, cvec *nsc, cxobj **xerr);
 int api_path2xpath(char *api_path, yang_stmt *yspec, char **xpath, char **namespace);
 int api_path2xml(char *api_path, yang_stmt *yspec, cxobj *xtop, 
 		 yang_class nodeclass, int strict, cxobj **xpathp, yang_stmt **ypathp);
diff --git a/lib/clixon/clixon_yang_module.h b/lib/clixon/clixon_yang_module.h
index da53e7bd..92186811 100644
--- a/lib/clixon/clixon_yang_module.h
+++ b/lib/clixon/clixon_yang_module.h
@@ -46,9 +46,9 @@
  * Types
  */
 
-/* Struct contataining module state differences between two modules or two 
+/* Struct containing module state differences between two modules or two 
  * revisions of same module. 
- * This is in state of flux so it needss to be conatained and easily changed.
+ * This is in state of flux so it needs to be contained and easily changed.
  */
 typedef struct {
     cxobj *md_del;   /* yang module state deletes */
diff --git a/lib/src/clixon_datastore_read.c b/lib/src/clixon_datastore_read.c
index 7d6ac95d..2150502c 100644
--- a/lib/src/clixon_datastore_read.c
+++ b/lib/src/clixon_datastore_read.c
@@ -141,9 +141,15 @@ xml_copy_marked(cxobj *x0,
     int        iskey;
     yang_stmt *yt;
     char      *name;
+    char      *prefix;
 
     assert(x0 && x1);
     yt = xml_spec(x0); /* can be null */
+    /* Copy prefix*/
+    if ((prefix = xml_prefix(x0)) != NULL)
+	if (xml_prefix_set(x1, prefix) < 0)
+	    goto done;
+    
     /* Copy all attributes */
     x = NULL;
     while ((x = xml_child_each(x0, x, CX_ATTR)) != NULL) {
diff --git a/lib/src/clixon_datastore_write.c b/lib/src/clixon_datastore_write.c
index b7e943ff..7954d0c4 100644
--- a/lib/src/clixon_datastore_write.c
+++ b/lib/src/clixon_datastore_write.c
@@ -74,6 +74,7 @@
 #include "clixon_json.h"
 #include "clixon_nacm.h"
 #include "clixon_netconf_lib.h"
+#include "clixon_yang_type.h"
 #include "clixon_yang_module.h"
 #include "clixon_xml_nsctx.h"
 #include "clixon_xml_map.h"
@@ -83,45 +84,6 @@
 #include "clixon_datastore_read.h"
 #include "clixon_datastore_tree.h"
 
-/*! Replace all xmlns attributes in x0 with xmlns attributes in x1
- * This is an embryo of code to actually check if namespace binding is canonical
- * and if it is not, either return error or transform to canonical.
- * "Canonical" meaning comply to the yang module prefixes.
- * The current code does not really do anything useful
- */
-static int
-replace_xmlns(cxobj *x0,
-	      cxobj *x1)
-{
-    int    retval = -1;
-    cxobj *x = NULL;
-    cxobj *xcopy;
-    int    i;
-
-    for (i=0; i<xml_child_nr(x0); ){
-	x = xml_child_i(x0, i);
-	if (!isxmlns(x)){
-	    i++;
-	    continue;
-	}
-	xml_rm(x);
-	xml_free(x);
-    }
-    x = NULL;
-    while ((x = xml_child_each(x1, x, CX_ATTR)) != NULL) {
-	/* split and only add xmlns= and xmlns:x= attributes! */
-	if (!isxmlns(x))
-	    continue;
-	if ((xcopy = xml_new(xml_name(x), x0, xml_spec(x))) == NULL)
-	    goto done;
-	if (xml_copy(x, xcopy) < 0) /* recursion */
-	    goto done;
-    }
-    retval = 0;
- done:
-    return retval;
-}
-
 /*! Given an attribute name and its expected namespace, find its value
  * 
  * An attribute may have a prefix(or NULL). The routine finds the associated
@@ -171,6 +133,206 @@ attr_ns_value(cxobj *x,
     goto done;
 }
 
+/*! Given a src node x0 and a target node x1, assign (optional) prefix and namespace
+ * @param[in]  x0       Source XML tree
+ * @param[in]  x1       Target XML tree
+ * 1. Find N=namespace(x0)
+ * 2. Detect if N is declared in x1 parent
+ * 3. If yes, assign prefix to x1
+ * 4. If no, create new prefix/namespace binding and assign that to x1p (x1 if x1p is root)
+ * 5. Add prefix to x1, if any
+ * 6. Ensure x1 cache is updated
+ * @note switch use of x0 and x1 compared to datastore text_modify
+ * @see xml2ns
+ * XXX: fail handling: 		if (netconf_data_missing(cbret, NULL, "Data does not exist; cannot delete resource") < 0)
+		    goto done;
+
+ */
+static int
+check_namespaces(cxobj *x0,
+		 cxobj *x1,
+		 cxobj *x1p)
+{
+    int   retval = -1;
+    char  *namespace = NULL;
+    char  *prefix0 = NULL;;
+    char  *prefix10 = NULL; /* extra just for malloc problem */
+    char  *prefix1 = NULL;;
+    cvec  *nsc0 = NULL;
+    cvec  *nsc = NULL;
+    cxobj *xa = NULL;
+    cxobj *x;
+    int   isroot;
+
+    /* XXX: need to identify root better than hiereustics and strcmp,... */
+    isroot = xml_parent(x1p)==NULL &&
+	strcmp(xml_name(x1p), "config") == 0 &&
+	xml_prefix(x1p)==NULL;
+
+    /* 1. Find N=namespace(x0) */
+    prefix0 = xml_prefix(x0);
+    if (xml2ns(x0, prefix0, &namespace) < 0)
+	goto done;
+    if (namespace == NULL){
+	clicon_err(OE_XML, ENOENT, "No namespace found for prefix:%s",
+		   prefix0?prefix0:"NULL");
+	goto done;
+    }
+    /* 2. Detect if namespace is declared in x1:s parent */
+    if (xml2prefix(x1p, namespace, &prefix10) == 1){ 
+	if (prefix10){
+	    if ((prefix1 = strdup(prefix10)) == NULL){
+		clicon_err(OE_UNIX, errno, "strdup");
+		goto done;
+	    }
+	}
+	else
+	    prefix1 = NULL;
+	/* 3. If yes, assign prefix to x1 */
+	if (prefix1 && xml_prefix_set(x1, prefix1) < 0)
+	    goto done;
+	/* And copy namespace context from parent to child */
+	if ((nsc0 = nscache_get_all(x1p)) != NULL){
+	    if ((nsc = cvec_dup(nsc0)) == NULL){
+		clicon_err(OE_UNIX, errno, "cvec_dup");
+		goto done;
+	    }
+	    nscache_replace(x1, nsc);
+	}
+	/* Just in case */
+	if (nscache_set(x1, prefix1, namespace) < 0)
+	    goto done;
+    }
+    else{
+	/* 4. If no, create new prefix/namespace binding and assign that to x1p
+	 * use modules own default prefix (some chance for clash)
+	 */
+	if (prefix0 == NULL && !isroot){
+	    assert(xml_spec(x1) != NULL);
+	    prefix0 = yang_find_myprefix(xml_spec(x1));	    
+	}
+	if (prefix0)
+	    if ((prefix1 = strdup(prefix0)) == NULL){
+		clicon_err(OE_UNIX, errno, "strdup");
+		goto done;
+	    }
+	    
+	/* Add binding to x1p. We add to parent due to heurestics, so we dont
+	 * end up in adding it to large number of siblings 
+	 */
+	if (isroot)
+	    x = x1;  
+	else
+	    x = x1p;
+	if (nscache_set(x, prefix1, namespace) < 0)
+	    goto done;
+	if (x == x1p){
+	    if ((nsc0 = nscache_get_all(x1p)) != NULL)
+		if ((nsc = cvec_dup(nsc0)) == NULL){
+		    clicon_err(OE_UNIX, errno, "cvec_dup");
+		    goto done;
+		}
+	    /* Copy x1p cache to x1 */
+	    nscache_replace(x1, nsc);
+	}
+	/* Create xmlns attribute to x1p/x1 XXX same code v */
+	if (prefix1){
+	    if ((xa = xml_new(prefix1, x, NULL)) == NULL)
+		goto done;
+	    if (xml_prefix_set(xa, "xmlns") < 0)
+		goto done;
+	}
+	else{
+	    if ((xa = xml_new("xmlns", x, NULL)) == NULL)
+		goto done;
+	}
+	xml_type_set(xa, CX_ATTR);
+	if (xml_value_set(xa, namespace) < 0)
+	    goto done;
+	xml_sort(x, NULL); /* Ensure attr is first / XXX xml_insert? */
+
+	/* 5. Add prefix to x1, if any */
+	if (prefix1 && xml_prefix_set(x1, prefix1) < 0)
+	    goto done;
+    }
+    /* 6. Ensure x1 cache is updated (I think it is done w xmlns_set above) */
+    retval = 0;
+ done:
+    if (prefix1)
+	free(prefix1);
+    return retval;
+}
+
+static int
+check_identityref(cxobj     *x0,
+		  cxobj     *x1,
+		  cxobj     *x1p,		  
+		  char      *x1bstr,
+		  yang_stmt *y)
+{
+    int        retval = -1;
+    yang_stmt *yrestype = NULL;
+    char      *prefix = NULL;
+    char      *ns0 = NULL;
+    char      *ns1 = NULL;
+    cxobj     *xa;
+    cxobj     *x;
+    int        isroot;
+
+    /* XXX: need to identify root better than hiereustics and strcmp,... */
+    isroot = xml_parent(x1p)==NULL &&
+	strcmp(xml_name(x1p), "config") == 0 &&
+	xml_prefix(x1p)==NULL;
+    if (yang_type_get(y, NULL, &yrestype,
+		      NULL, NULL, NULL, NULL, NULL) < 0)
+	goto done;
+    if (strcmp(yang_argument_get(yrestype), "identityref") != 0)
+	goto ok; /* skip */
+    if (nodeid_split(x1bstr, &prefix, NULL) < 0)
+	goto done;
+    if (prefix == NULL)
+	goto ok; /* skip */
+    if (xml2ns(x0, prefix, &ns0) < 0)
+	goto done;
+    if (xml2ns(x1, prefix, &ns1) < 0)
+	goto done;
+    if (ns0 != NULL){
+	if (ns1){
+	    if (strcmp(ns0, ns1)){
+		clicon_err(OE_YANG, EFAULT, "identity namespace collision: %s: %s vs %s", x1bstr, ns0, ns1);
+		goto done;
+	    }
+	}
+	else{
+	    if (isroot)
+		x = x1;
+	    else
+		x = x1p;
+	    if (nscache_set(x, prefix, ns0) < 0)
+		goto done;
+	    /* Create xmlns attribute to x1 XXX same code ^*/
+	    if (prefix){
+		if ((xa = xml_new(prefix, x, NULL)) == NULL)
+		    goto done;
+		if (xml_prefix_set(xa, "xmlns") < 0)
+		    goto done;
+	    }
+	    else{
+		if ((xa = xml_new("xmlns", x, NULL)) == NULL)
+		    goto done;
+	    }
+	    xml_type_set(xa, CX_ATTR);
+	    if (xml_value_set(xa, ns0) < 0)
+		goto done;
+	    xml_sort(x, NULL); /* Ensure attr is first / XXX xml_insert? */
+	}
+    }
+ ok:
+    retval = 0;
+ done:
+    return retval;
+}
+
 /*! Modify a base tree x0 with x1 with yang spec y according to operation op
  * @param[in]  th       Datastore text handle
  * @param[in]  x0       Base xml tree (can be NULL in add scenarios)
@@ -208,12 +370,12 @@ text_modify(clicon_handle       h,
     char      *opstr = NULL;
     char      *x1name;
     char      *x1cname; /* child name */
-    cxobj     *x0a; /* attribute */
-    cxobj     *x1a; /* attribute */
+    //    cxobj     *x0a; /* attribute */
+    //    cxobj     *x1a; /* attribute */
     cxobj     *x0c; /* base child */
     cxobj     *x0b; /* base body */
     cxobj     *x1c; /* mod child */
-    char      *xns;  /* namespace */
+    //    char      *xns;  /* namespace */
     char      *x0bstr; /* mod body string */
     char      *x1bstr; /* mod body string */
     yang_stmt *yc;  /* yang child */
@@ -303,7 +465,6 @@ text_modify(clicon_handle       h,
 		}
 	    } /* OP_MERGE & insert */
 	case OP_NONE: /* fall thru */
-
 	    if (x0==NULL){
 		if ((op != OP_NONE) && !permit && xnacm){
 		    if ((ret = nacm_datanode_write(NULL, x1, NACM_CREATE, username, xnacm, cbret)) < 0) 
@@ -316,32 +477,14 @@ text_modify(clicon_handle       h,
 		   copied (see changed conditional below) */
 		if ((x0 = xml_new(x1name, NULL, (yang_stmt*)y0)) == NULL)
 		    goto done;
-		changed++;
-
-		/* Copy xmlns attributes ONLY, not op/insert etc */
-		x1a = NULL;
-		while ((x1a = xml_child_each(x1, x1a, CX_ATTR)) != NULL) 
-		    if (strcmp(xml_name(x1a),"xmlns")==0 ||
-			((xns = xml_prefix(x1a)) && strcmp(xns, "xmlns")==0)){
-#if 1 /* XXX Kludge to NOT copy RFC7950 xmlns:yang insert/key/value namespaces */
-			if (strcmp(xml_value(x1a), YANG_XML_NAMESPACE)==0  ||
-			    strcmp(xml_value(x1a), NETCONF_BASE_NAMESPACE)==0)
-			    continue;
-#endif
-			if ((x0a = xml_dup(x1a)) == NULL)
-			    goto done;
-			if (xml_addsub(x0, x0a) < 0)
-			    goto done;
-		    }
-
-#if 0
-		/* If it is key I dont want to mark it */
-		if ((iamkey=yang_key_match(yang_parent_get(y0), x1name)) < 0)
+		/* Get namespace from x1
+		 * Check if namespace exists in x0 parent
+		 * if not add new binding and replace in x0.
+		 */
+		if (check_namespaces(x1, x0, x0p) < 0)
 		    goto done;
-		if (!iamkey && op==OP_NONE)
-#else
+		changed++;
 		if (op==OP_NONE)
-#endif
 		    xml_flag_set(x0, XML_FLAG_NONE); /* Mark for potential deletion */
 		if (x1bstr){ /* empty type does not have body */
 		    if ((x0b = xml_new("body", x0, NULL)) == NULL)
@@ -349,17 +492,9 @@ text_modify(clicon_handle       h,
 		    xml_type_set(x0b, CX_BODY);
 		}
 	    }
-	    else {  /* if change existing node, replace xmlns attributes 
-		     * This is only done for leaf/leaf-list now, eg terminals
-		     * and is only an embryo of checking canonical namespace
-		     * bindings.
-		     * But it does catch some cornercases where a new
-		     * namespace binding is replacing an old for eg identityref
-		     */
-		if (replace_xmlns(x0, x1) < 0)
-		    goto done;
-	    }
 	    if (x1bstr){
+		if (check_identityref(x1, x0, x0p, x1bstr, y0) < 0)
+		    goto done;
 		if ((x0b = xml_body_get(x0)) != NULL){
 		    x0bstr = xml_value(x0b);
 		    if (x0bstr==NULL || strcmp(x0bstr, x1bstr)){
@@ -486,6 +621,8 @@ text_modify(clicon_handle       h,
 		}
 		if ((x0 = xml_new(x1name, x0p, (yang_stmt*)y0)) == NULL)
 		    goto done;
+		// XXX		if (check_namespaces(x1, x0) < 0)
+		//		    goto done;
 		if (xml_copy(x1, x0) < 0)
 		    goto done;
 		break;
@@ -505,21 +642,12 @@ text_modify(clicon_handle       h,
 		if ((x0 = xml_new(x1name, NULL, (yang_stmt*)y0)) == NULL)
 		    goto done;
 		changed++;
-		/* Copy xmlns attributes  */
-		x1a = NULL;
-		while ((x1a = xml_child_each(x1, x1a, CX_ATTR)) != NULL) 
-		    if (strcmp(xml_name(x1a),"xmlns")==0 ||
-			((xns = xml_prefix(x1a)) && strcmp(xns, "xmlns")==0)){
-#if 1 /* XXX Kludge to NOT copy RFC7950 xmlns:yang insert/key/value namespaces */
-			if (strcmp(xml_value(x1a), YANG_XML_NAMESPACE)==0 ||
-			    strcmp(xml_value(x1a), NETCONF_BASE_NAMESPACE)==0)
-			    continue;
-#endif
-			if ((x0a = xml_dup(x1a)) == NULL)
-			    goto done;
-			if (xml_addsub(x0, x0a) < 0)
-			    goto done;
-		    }
+		/* Get namespace from x1
+		 * Check if namespace exists in x0 parent
+		 * if not add new binding and replace in x0.
+		 */
+		if (check_namespaces(x1, x0, x0p) < 0)
+		    goto done;
 		if (op==OP_NONE)
 		    xml_flag_set(x0, XML_FLAG_NONE); /* Mark for potential deletion */
 	    }
@@ -534,23 +662,30 @@ text_modify(clicon_handle       h,
 	    i = 0;
 	    while ((x1c = xml_child_each(x1, x1c, CX_ELMNT)) != NULL) {
 		x1cname = xml_name(x1c);
-		/* Get yang spec of the child */
+		/* Get yang spec of the child by child matching */
 		if ((yc = yang_find_datanode(y0, x1cname)) == NULL){
 		    clicon_err(OE_YANG, errno, "No yang node found: %s", x1cname);
 		    goto done;
 		}
+		/* There is a cornercase (eg augment) of multi-namespace trees where
+		 * the yang child has a different namespace.
+		 * As an alternative, return in populate where this is detected first time.
+		 */
+		if (yc != xml_spec(x1c)){
+		    clicon_err(OE_YANG, errno, "XML node %s not in namespace %s",
+			       x1cname, yang_find_mynamespace(y0));
+		    goto done;
+		}
 		/* See if there is a corresponding node in the base tree */
 		x0c = NULL;
 		if (match_base_child(x0, x1c, yc, &x0c) < 0)
 		    goto done;
-#if 1
 		if (x0c && (yc != xml_spec(x0c))){
 		    /* There is a match but is should be replaced (choice)*/
 		    if (xml_purge(x0c) < 0)
 			goto done;
 		    x0c = NULL;
 		}
-#endif
 		x0vec[i++] = x0c; /* != NULL if x0c is matching x1c */
 	    }
 	    /* Second pass: Loop through children of the x1 modification tree again
@@ -725,14 +860,12 @@ text_modify_top(clicon_handle       h,
 	/* See if there is a corresponding node in the base tree */
 	if (match_base_child(x0, x1c, yc, &x0c) < 0)
 	    goto done;
-#if 1
 	if (x0c && (yc != xml_spec(x0c))){
 	    /* There is a match but is should be replaced (choice)*/
 	    if (xml_purge(x0c) < 0)
 		goto done;
 	    x0c = NULL;
 	}
-#endif
 	if ((ret = text_modify(h, x0c, yc, x0, x1c, op,
 			       username, xnacm, permit, cbret)) < 0)
 	    goto done;
diff --git a/lib/src/clixon_proto_client.c b/lib/src/clixon_proto_client.c
index 40a8ee89..ccbcc32c 100644
--- a/lib/src/clixon_proto_client.c
+++ b/lib/src/clixon_proto_client.c
@@ -584,7 +584,8 @@ clicon_rpc_get(clicon_handle   h,
     if ((username = clicon_username_get(h)) != NULL)
 	cprintf(cb, " username=\"%s\"", username);
     if (namespace)
-	cprintf(cb, " xmlns:nc=\"%s\"", NETCONF_BASE_NAMESPACE);
+	cprintf(cb, " xmlns:%s=\"%s\"",
+		NETCONF_BASE_PREFIX, NETCONF_BASE_NAMESPACE);
     cprintf(cb, "><get");
     /* Clixon extension, content=all,config, or nonconfig */
     if (content != -1)
@@ -627,6 +628,79 @@ clicon_rpc_get(clicon_handle   h,
     return retval;
 }
 
+int
+clicon_rpc_get_nsc(clicon_handle   h, 
+		   char           *xpath,
+		   cvec           *nsc, /* namespace context for filter */
+		   netconf_content content,
+		   int32_t         depth,
+		   cxobj         **xt)
+{
+    int                retval = -1;
+    struct clicon_msg *msg = NULL;
+    cbuf              *cb = NULL;
+    cxobj             *xret = NULL;
+    cxobj             *xd;
+    char              *username;
+    cg_var            *cv = NULL;
+    char              *prefix;
+
+    if ((cb = cbuf_new()) == NULL)
+	goto done;
+    cprintf(cb, "<rpc");
+    if ((username = clicon_username_get(h)) != NULL)
+	cprintf(cb, " username=\"%s\"", username);
+    cprintf(cb, " xmlns:%s=\"%s\"",
+	    NETCONF_BASE_PREFIX, NETCONF_BASE_NAMESPACE);
+    cprintf(cb, "><get");
+    /* Clixon extension, content=all,config, or nonconfig */
+    if (content != -1)
+	cprintf(cb, " content=\"%s\"", netconf_content_int2str(content));
+    /* Clixon extension, depth=<level> */
+    if (depth != -1)
+	cprintf(cb, " depth=\"%d\"", depth);
+    cprintf(cb, ">");
+    if (xpath && strlen(xpath)) {
+	cprintf(cb, "<%s:filter %s:type=\"xpath\" %s:select=\"%s\"",
+		NETCONF_BASE_PREFIX, NETCONF_BASE_PREFIX, NETCONF_BASE_PREFIX,
+		xpath);
+
+	while ((cv = cvec_each(nsc, cv)) != NULL){
+	    cprintf(cb, " xmlns");
+	    if ((prefix = cv_name_get(cv)))
+		cprintf(cb, ":%s", prefix);
+	    cprintf(cb, "=\"%s\"", cv_string_get(cv));
+	}
+	cprintf(cb, "/>");
+    }
+    cprintf(cb, "</get></rpc>");
+    if ((msg = clicon_msg_encode("%s", cbuf_get(cb))) == NULL)
+	goto done;
+    if (clicon_rpc_msg(h, msg, &xret, NULL) < 0)
+	goto done;
+    /* Send xml error back: first check error, then ok */
+    if ((xd = xpath_first(xret, "/rpc-reply/rpc-error")) != NULL)
+	xd = xml_parent(xd); /* point to rpc-reply */
+    else if ((xd = xpath_first(xret, "/rpc-reply/data")) == NULL)
+	if ((xd = xml_new("data", NULL, NULL)) == NULL)
+	    goto done;
+    if (xt){
+	if (xml_rm(xd) < 0)
+	    goto done;
+	*xt = xd;
+    }
+    retval = 0;
+  done:
+    if (cb)
+	cbuf_free(cb);
+    if (xret)
+	xml_free(xret);
+    if (msg)
+	free(msg);
+    return retval;
+}
+
+
 /*! Close a (user) session
  * @param[in] h        CLICON handle
  * @retval    0        OK
diff --git a/lib/src/clixon_xml.c b/lib/src/clixon_xml.c
index c5b1715f..f674b219 100644
--- a/lib/src/clixon_xml.c
+++ b/lib/src/clixon_xml.c
@@ -197,9 +197,9 @@ xml_name_set(cxobj *xn,
     return 0;
 }
 
-/*! Get namespace of xnode
- * @param[in]  xn    xml node
- * @retval     namespace of xml node
+/*! Get prefix of xnode
+ * @param[in]  xn     xml node
+ * @retval     prefix of xml node
  */
 char*
 xml_prefix(cxobj *xn)
@@ -207,9 +207,9 @@ xml_prefix(cxobj *xn)
     return xn->x_prefix;
 }
 
-/*! Set name space of xnode, namespace is copied
+/*! Set prefix of xnode, prefix is copied
  * @param[in]  xn         xml node
- * @param[in]  localname  new namespace, null-terminated string, copied by function
+ * @param[in]  localname  new prefix, null-terminated string, copied by function
  * @retval     -1         on error with clicon-err set
  * @retval     0          OK
  */
@@ -230,14 +230,14 @@ xml_prefix_set(cxobj *xn,
     return 0;
 }
 
-/*! Get cached namespace
+/*! Get cached namespace (given prefix)
  * @param[in] x      XML node
  * @param[in] prefix Namespace prefix, or NULL for default
  * @retval    ns     Cached namespace
  * @retval    NULL   No namespace found (not cached or not found)
  * @note may want to distinguish between not set cache and no namespace?
  */
-static char*
+char*
 nscache_get(cxobj *x,
 	    char  *prefix)
 {
@@ -246,6 +246,35 @@ nscache_get(cxobj *x,
     return NULL;
 }
 
+/*! Get cached prefix (given namespace) 
+ * @param[in]  x         XML node
+ * @param[in]  namespace
+ * @param[out] prefix
+ * @retval     0      No prefix found
+ * @retval     1      Prefix found
+ */
+int
+nscache_get_prefix(cxobj *x,
+		   char  *namespace,
+		   char **prefix)
+{
+    if (x->x_ns_cache != NULL)
+	return xml_nsctx_get_prefix(x->x_ns_cache, namespace, prefix);
+    return 0;
+}
+
+/*! Dump whole namespacet context cache of one xml node 
+ * @param[in]  x    XML node
+ * @retval     nsc  Whole namespace context of x
+ * @retval     NULL Empty nsc
+ * @see nscache_get  For a single prefix
+ */
+cvec *
+nscache_get_all(cxobj *x)
+{
+    return x->x_ns_cache;
+}
+
 /*! Set cached namespace for specific namespace. Replace if necessary
  * @param[in] x         XML node
  * @param[in] prefix    Namespace prefix, or NULL for default
@@ -254,7 +283,7 @@ nscache_get(cxobj *x,
  * @retval   -1         Error
  * @see nscache_replace  to replace the whole context
  */
-static int
+int
 nscache_set(cxobj *x,
 	    char  *prefix,
 	    char  *namespace)
@@ -281,7 +310,7 @@ nscache_set(cxobj *x,
  */
 int
 nscache_replace(cxobj *x,
-		cvec *nsc)
+		cvec  *nsc)
 {
     int     retval = -1;
 
@@ -405,6 +434,63 @@ xmlns_set(cxobj *x,
     return retval;
 }
 
+/*! Get namespace given prefix recursively 
+ * @param[in]  xn        XML node
+ * @param[in]  namespace Namespace
+ * @param[out] prefixp   Pointer to prefix if found
+ * @retval    -1         Error
+ * @retval     0         No namespace found
+ * @retval     1         Namespace found
+ */
+int
+xml2prefix(cxobj *xn,
+	   char  *namespace,
+	   char **prefixp)
+{
+    int    retval = -1;
+    cxobj *xa = NULL;
+    char  *prefix = NULL;
+
+    while (xn != NULL){
+	if (nscache_get_prefix(xn, namespace, &prefix) == 1) /* found */
+	    goto found;
+	//	if (xn->x_ns_cache == NULL){ /* Look in node */
+	    xa = NULL;
+	    while ((xa = xml_child_each(xn, xa, CX_ATTR)) != NULL) {
+		/* xmlns=namespace */
+		if (strcmp("xmlns", xml_name(xa)) == 0){ 
+		    if (strcmp(xml_value(xa), namespace) == 0){
+    clicon_debug(1, "%sA NULL %s", __FUNCTION__, namespace);
+			if (nscache_set(xn, NULL, namespace) < 0)
+			    goto done;
+			prefix = NULL;
+			goto found;
+		    }
+
+		}
+		/* xmlns:prefix=namespace */
+		else if (strcmp("xmlns", xml_prefix(xa)) == 0){ 
+		    if (strcmp(xml_value(xa), namespace) == 0){
+			prefix = xml_name(xa);
+			assert(strcmp(prefix, "xmlns"));
+			if (nscache_set(xn, prefix, namespace) < 0)
+			    goto done;
+			goto found;
+		    }
+		}
+	    }
+	    // }
+	xn = xml_parent(xn);
+    }
+    retval = 0;
+ done:
+    return retval;
+ found:
+    *prefixp = prefix;
+    retval = 1;
+    goto done;
+}
+
 /*! See if xmlns:[<localname>=]<uri> exists, if so return <uri>
  *
  * @param[in]  xn   XML node
@@ -982,6 +1068,7 @@ int
 xml_addsub(cxobj *xp, 
 	   cxobj *xc)
 {
+    int retval = -1;
     cxobj *oldp;
     int    i;
     char  *pns = NULL; /* parent namespace */
@@ -1000,13 +1087,14 @@ xml_addsub(cxobj *xp,
     /* Add xc to new parent */
     if (xp){
 	if (xml_child_append(xp, xc) < 0)
-	    return -1;
+	    goto done;
 	/* Set new parent in child */
 	xml_parent_set(xc, xp);
 	/* Ensure default namespace is not duplicated 
 	 * here only remove duplicate default namespace, there may be more */
 	/* 1. Get parent default namespace */
-	xml2ns(xp, NULL, &pns);
+	if (xml2ns(xp, NULL, &pns) < 0)
+	    goto done;
 	/* 2. Get child default namespace */
 	if (pns &&
 	    (xa = xml_find_type(xc, NULL, "xmlns", CX_ATTR)) != NULL &&
@@ -1016,9 +1104,11 @@ xml_addsub(cxobj *xp,
 		xml_purge(xa); 
 	}
 	/* clear namespace context cache of child */
-	nscache_clear(xp);
+	nscache_clear(xc);
     }
-    return 0;
+    retval = 0;
+ done:
+    return retval;
 }
 
 /*! Wrap a new node between a parent xml node (xp) and all its children
diff --git a/lib/src/clixon_xml_map.c b/lib/src/clixon_xml_map.c
index bbc86241..0c02bfe5 100644
--- a/lib/src/clixon_xml_map.c
+++ b/lib/src/clixon_xml_map.c
@@ -1749,54 +1749,59 @@ yang2api_path_fmt_1(yang_stmt *ys,
 		    cbuf      *cb)
 {
     yang_stmt *yp; /* parent */
+    yang_stmt *ymod;
     int        i;
     cvec      *cvk = NULL; /* vector of index keys */
     int        retval = -1;
 
-    if ((yp = ys->ys_parent) == NULL){
-	clicon_err(OE_YANG, EINVAL, "yang expected parent %s", ys->ys_argument);
+    if ((yp = yang_parent_get(ys)) == NULL){
+	clicon_err(OE_YANG, EINVAL, "yang expected parent %s", yang_argument_get(ys));
 	goto done;
     }
     if (yp != NULL && /* XXX rm */
-	yp->ys_keyword != Y_MODULE && 
-	yp->ys_keyword != Y_SUBMODULE){
+	yang_keyword_get(yp) != Y_MODULE && 
+	yang_keyword_get(yp) != Y_SUBMODULE){
+
 	if (yang2api_path_fmt_1((yang_stmt *)yp, 1, cb) < 0) /* recursive call */
 	    goto done;
-	if (yp->ys_keyword != Y_CHOICE && yp->ys_keyword != Y_CASE){
+	if (yang_keyword_get(yp) != Y_CHOICE && yang_keyword_get(yp) != Y_CASE){
 #if 0
 	    /* In some cases, such as cli_show_auto, a trailing '/' should
 	     * NOT be present if ys is a key in a list.
 	     * But in other cases (I think most), the / should be there,
 	     * so a patch is added in cli_show_auto instead.
 	     */
-	    if (ys->ys_keyword == Y_LEAF && yp && 
-		yp->ys_keyword == Y_LIST &&
+		if (yang_keyword_get(ys) == Y_LEAF && yp && 
+		    yang_keyword_get(yp) == Y_LIST &&
 		yang_key_match(yp, ys->ys_argument) == 1)
 		;
 	    else
 #endif
-		cprintf(cb, "/"); 
+		cprintf(cb, "/");
 	}
+	/* If parent namespace/module is different from child -> add child prefix */
+	if (ys_real_module(yp) != (ymod = ys_real_module(ys)))
+	    cprintf(cb, "%s:", yang_argument_get(ymod));
     }
     else /* top symbol - mark with name prefix */
-	cprintf(cb, "/%s:", yp->ys_argument);
+	cprintf(cb, "/%s:", yang_argument_get(yp));
 
     if (inclkey){
-	if (ys->ys_keyword != Y_CHOICE && ys->ys_keyword != Y_CASE)
-	    cprintf(cb, "%s", ys->ys_argument);
+	if (yang_keyword_get(ys) != Y_CHOICE && yang_keyword_get(ys) != Y_CASE)
+	    cprintf(cb, "%s", yang_argument_get(ys));
     }
     else{
-	if (ys->ys_keyword == Y_LEAF && yp && 
-	    yp->ys_keyword == Y_LIST){
-	    if (yang_key_match(yp, ys->ys_argument) == 0)
-		cprintf(cb, "%s", ys->ys_argument); /* Not if leaf and key */
+	if (yang_keyword_get(ys) == Y_LEAF && yp && 
+	    yang_keyword_get(yp) == Y_LIST){
+	    if (yang_key_match(yp, yang_argument_get(ys)) == 0)
+		cprintf(cb, "%s", yang_argument_get(ys)); /* Not if leaf and key */
 	}
 	else  
-	    if (ys->ys_keyword != Y_CHOICE && ys->ys_keyword != Y_CASE)
-		cprintf(cb, "%s", ys->ys_argument);
+	    if (yang_keyword_get(ys) != Y_CHOICE && yang_keyword_get(ys) != Y_CASE)
+		cprintf(cb, "%s", yang_argument_get(ys));
     }
 
-    switch (ys->ys_keyword){
+    switch (yang_keyword_get(ys)){
     case Y_LIST:
 	cvk = ys->ys_cvec; /* Use Y_LIST cache, see ys_populate_list() */
 	if (cvec_len(cvk))
@@ -2168,6 +2173,8 @@ xml_default(cxobj *xt,
     cxobj     *xb;
     char      *str;
     int        added=0;
+    char      *namespace;
+    char      *prefix;
     
     if ((ys = (yang_stmt*)xml_spec(xt)) == NULL){
 	retval = 0;
@@ -2183,9 +2190,16 @@ xml_default(cxobj *xt,
 	    assert(y->ys_cv);
 	    if (!cv_flag(y->ys_cv, V_UNSET)){  /* Default value exists */
 		if (!xml_find(xt, y->ys_argument)){
-
 		    if ((xc = xml_new(y->ys_argument, NULL, y)) == NULL)
 			goto done;
+		    /* assign right prefix */
+		    if ((namespace = yang_find_mynamespace(y)) != NULL){
+			prefix = NULL;
+			if (xml2prefix(xt, namespace, &prefix))
+			    if (xml_prefix_set(xc, prefix) < 0)
+				goto done;
+		    }
+
 		    xml_flag_set(xc, XML_FLAG_DEFAULT);
 		    if ((xb = xml_new("body", xc, NULL)) == NULL)
 			goto done;
@@ -2336,6 +2350,8 @@ xml_spec_populate(cxobj  *x,
     yang_stmt *ymod;         /* yang module */
     cxobj     *xp = NULL;    /* xml parent */
     char      *name;
+    char      *ns = NULL;    /* XML namespace of x */
+    char      *nsy = NULL;   /* Yang namespace of x */
 
     yspec = (yang_stmt*)arg;
     xp = xml_parent(x);
@@ -2343,8 +2359,11 @@ xml_spec_populate(cxobj  *x,
 #ifdef DEBUG
     clicon_debug(1, "%s name:%s", __FUNCTION__, name);
 #endif
-    if (xp && (yparent = xml_spec(xp)) != NULL)
+    if (xml2ns(x, xml_prefix(x), &ns) < 0)
+	goto done;
+    if (xp && (yparent = xml_spec(xp)) != NULL){
 	y = yang_find_datanode(yparent, name);
+    }
     else if (yspec){
 	if (ys_module_by_xml(yspec, x, &ymod) < 0)
 	    goto done;
@@ -2361,10 +2380,17 @@ xml_spec_populate(cxobj  *x,
 #endif
     }
     if (y) {
+	nsy = yang_find_mynamespace(y);
+	if (ns == NULL || nsy == NULL){
+	    clicon_err(OE_XML, EFAULT, "Namespace NULL");
+	    goto done;
+	}
 #ifdef DEBUG
 	clicon_debug(1, "%s y:%s", __FUNCTION__, yang_argument_get(y));
 #endif
-	xml_spec_set(x, y);
+	/* Assign spec only if namespaces match */
+	if (strcmp(ns, nsy) == 0)
+	    xml_spec_set(x, y);	    
     }
 #ifdef DEBUG
     else
@@ -2387,13 +2413,7 @@ xml_spec_populate(cxobj  *x,
  * @retval        0        Invalid api_path or associated XML, netconf error xml set
  * @retval       -1        Fatal error, clicon_err called
  *
- * @note both retval -1 set clicon_err, retval 0 sets netconf xml msg
- * @note Not proper namespace translation from api-path 2 xpath
- * It works like this:
- * Assume origin incoming path is 
- * "www.foo.com/restconf/a/b=c",  pi is 2 and pcvec is:
- *   ["www.foo.com" "restconf" "a" "b=c"]
- * which means the api-path is ["a" "b=c"] corresponding to "a/b=c"
+
  * @code
  *   cbuf *xpath = cbuf_new();
  *   cvec *cvv = NULL; 
@@ -2405,7 +2425,14 @@ xml_spec_populate(cxobj  *x,
  *     ... access xpath as cbuf_get(xpath) 
  *   cbuf_free(xpath)
  * @endcode
+ * It works like this:
+ * Assume origin incoming path is 
+ * "www.foo.com/restconf/a/b=c",  pi is 2 and pcvec is:
+ *   ["www.foo.com" "restconf" "a" "b=c"]
+ * which means the api-path is ["a" "b=c"] corresponding to "a/b=c"
  * @note "api-path" is "URI-encoded path expression" definition in RFC8040 3.5.3
+ * @note retval -1 sets clicon_err, retval 0 sets netconf xml msg
+ * @note Not proper namespace translation from api-path 2 xpath!!!
  * @see api_path2xml  For api-path to xml tree
  * @see api_path2xpath  Using strings as parameters
  */
@@ -2438,7 +2465,8 @@ api_path2xpath_cvv(cvec       *api_path,
 	nodeid = cv_name_get(cv);
 	if (nodeid_split(nodeid, &prefix, &name) < 0)
 	    goto done;
-	clicon_debug(1, "%s [%d] cvname: %s:%s", __FUNCTION__, i, prefix?prefix:"", name);
+	clicon_debug(1, "%s [%d] cvname: %s:%s",
+		     __FUNCTION__, i, prefix?prefix:"", name);
 	if (i == offset){ /* top-node */
 	    if (prefix == NULL){
 		if ((cberr = cbuf_new()) == NULL){
@@ -2536,6 +2564,170 @@ api_path2xpath_cvv(cvec       *api_path,
     goto done;
 }
 
+/*! Temp alternative to api_path2xpath_cvv */
+int
+api_path2xpath_cvv2(cvec       *api_path,
+		    int         offset,
+		    yang_stmt  *yspec,
+		    cbuf       *xpath,
+		    cvec       *nsc,
+		    cxobj     **xerr)
+{
+    int        retval = -1;
+    int        i;
+    cg_var    *cv;
+    char      *nodeid;
+    char      *prefix = NULL;  /* api-path (module) prefix */
+    char      *xprefix = NULL; /* xml xpath prefix */
+    char      *name = NULL;
+    cvec      *cvk = NULL; /* vector of index keys */
+    yang_stmt *y = NULL;
+    yang_stmt *ymod = NULL;
+    char      *val;
+    cg_var    *cvi;
+    char     **valvec = NULL;
+    int        vi;
+    int        nvalvec;
+    cbuf      *cberr = NULL;
+    char      *namespace = NULL;
+			
+    for (i=offset; i<cvec_len(api_path); i++){
+        cv = cvec_i(api_path, i);
+	nodeid = cv_name_get(cv);
+	/* api-path: prefix points to module */
+	if (nodeid_split(nodeid, &prefix, &name) < 0)
+	    goto done;
+	clicon_debug(1, "%s [%d] cvname: %s:%s",
+		     __FUNCTION__, i, prefix?prefix:"", name);
+	/* top-node must have prefix */
+	if (i == offset && prefix == NULL){
+	    if ((cberr = cbuf_new()) == NULL){
+		clicon_err(OE_UNIX, errno, "cbuf_new");
+		goto done;
+	    }
+	    cprintf(cberr, "'%s': Expected prefix:name", nodeid);
+	    if (netconf_invalid_value_xml(xerr, "application", cbuf_get(cberr)) < 0)
+		goto done;
+	    goto fail;
+	}
+	ymod = NULL;
+	if (prefix){ /* if prefix -> get module + change namespace */
+	    if ((ymod = yang_find_module_by_name(yspec, prefix)) == NULL){
+		if ((cberr = cbuf_new()) == NULL){
+		    clicon_err(OE_UNIX, errno, "cbuf_new");
+		    goto done;
+		}
+		cprintf(cberr, "No such yang module: %s", prefix);
+		if (netconf_invalid_value_xml(xerr, "application", cbuf_get(cberr)) < 0)
+		    goto done;
+		goto fail;
+	    }
+	    namespace = yang_find_mynamespace(ymod); /* change namespace */
+	}
+	if (i == offset && ymod) /* root */
+	    y = yang_find_datanode(ymod, name);
+	else
+	    y = yang_find_datanode(y, name);
+	if (y == NULL){
+	    if (netconf_unknown_element_xml(xerr, "application", name, "Unknown element") < 0)
+		goto done;
+	    goto fail;
+	}
+	/* Get XML/xpath prefix given namespace.
+	 * note different from api-path prefix
+	 */
+	if (xml_nsctx_get_prefix(nsc, namespace, &xprefix) == 0){
+
+	    xprefix = yang_find_myprefix(y);
+	    clicon_debug(1, "%s prefix not found add it %s", __FUNCTION__, xprefix);
+	    /* not found, add it to nsc  */
+	    if (xml_nsctx_set(nsc, xprefix, namespace) < 0)
+		goto done;
+	}
+	/* Check if has value, means '=' */
+        if (cv2str(cv, NULL, 0) > 0){
+            if ((val = cv2str_dup(cv)) == NULL)
+                goto done;
+	    switch (yang_keyword_get(y)){
+	    case Y_LIST:
+		/* Transform value "a,b,c" to "a" "b" "c" (nvalvec=3)
+		 * Note that vnr can be < length of cvk, due to empty or unset values
+		 */
+		if (valvec){ /* loop, valvec may have been used before */
+		    free(valvec);
+		    valvec = NULL;
+		}
+		if ((valvec = clicon_strsep(val, ",", &nvalvec)) == NULL)
+		    goto done;
+		cvk = y->ys_cvec; /* Use Y_LIST cache, see ys_populate_list() */
+		cvi = NULL;
+		/* Iterate over individual yang keys  */
+		cprintf(xpath, "/");
+		if (xprefix)
+		    cprintf(xpath, "%s:", xprefix);
+		cprintf(xpath, "%s", name);
+		vi = 0;
+		while ((cvi = cvec_each(cvk, cvi)) != NULL && vi<nvalvec){
+		    cprintf(xpath, "[");
+		    if (xprefix)
+			cprintf(xpath, "%s:", xprefix);
+		    cprintf(xpath, "%s='%s']", cv_string_get(cvi), valvec[vi++]);
+		}
+		break;
+	    case Y_LEAF_LIST: /* XXX: LOOP? */
+		cprintf(xpath, "/");
+		if (xprefix)
+		    cprintf(xpath, "%s:", xprefix);
+		cprintf(xpath, "%s", name);
+		if (val)
+		    cprintf(xpath, "[.='%s']", val);
+		else
+		    cprintf(xpath, "[.='']");
+		break;
+	    default:
+		if (i != offset)
+		    cprintf(xpath, "/");
+		if (xprefix)
+		    cprintf(xpath, "%s:", xprefix);
+		cprintf(xpath, "%s", name);
+		break;
+	    }
+	    if (val)
+		free(val);
+        }
+        else{
+	    if (i != offset)
+		cprintf(xpath, "/");
+	    if (xprefix)
+		cprintf(xpath, "%s:", xprefix);
+	    cprintf(xpath, "%s", name);
+	}
+	if (prefix){
+	    free(prefix);
+	    prefix = NULL;
+	}
+	if (name){
+	    free(name);
+	    name = NULL;
+	}
+    } /* for */
+    retval = 1; /* OK */
+ done:
+    clicon_debug(1, "%s retval:%d", __FUNCTION__, retval);
+    if (cberr != NULL)
+	cbuf_free(cberr);
+    if (valvec)
+	free(valvec);
+    if (prefix)
+	free(prefix);
+    if (name)
+	free(name);
+    return retval;
+ fail:
+    retval = 0; /* Validation failed */
+    goto done;
+}
+
 /*! Translate from restconf api-path to xml xpath and namespace
  * @param[in]  api_path  URI-encoded path expression" (RFC8040 3.5.3)
  * @param[in]  yspec     Yang spec
@@ -2674,7 +2866,6 @@ api_path2xml_vec(char             **vec,
 	}
 	namespace = yang_find_mynamespace(ymod);
 	y0 = ymod;
-
     }
     y = (nodeclass==YC_SCHEMANODE)?
 	yang_find_schemanode(y0, name):
@@ -2683,6 +2874,13 @@ api_path2xml_vec(char             **vec,
 	clicon_err(OE_YANG, EINVAL, "api-path name: '%s', no such yang element", name);
 	goto fail;
     }
+    if (prefix && namespace == NULL){
+	if ((ymod = yang_find_module_by_name(ys_spec(y0), prefix)) == NULL){
+	    clicon_err(OE_YANG, EINVAL, "api-path element prefix: '%s', no such yang module", prefix);
+	    goto fail;
+	}
+	namespace = yang_find_mynamespace(ymod);
+    }
     switch (y->ys_keyword){
     case Y_LEAF_LIST:
 	if (0 && restval==NULL){
diff --git a/lib/src/clixon_xml_nsctx.c b/lib/src/clixon_xml_nsctx.c
index db85456f..71b78bcb 100644
--- a/lib/src/clixon_xml_nsctx.c
+++ b/lib/src/clixon_xml_nsctx.c
@@ -94,8 +94,8 @@ xml_nsctx_get(cvec *cvv,
  * @note NULL is a valid prefix (default)
  */
 int
-xml_nsctx_get_prefix(cvec *cvv,
-		     char *namespace,
+xml_nsctx_get_prefix(cvec  *cvv,
+		     char  *namespace,
 		     char **prefix)
 {
     cg_var *cv = NULL;
diff --git a/lib/src/clixon_xml_sort.c b/lib/src/clixon_xml_sort.c
index b79f0a81..0f1bb97a 100644
--- a/lib/src/clixon_xml_sort.c
+++ b/lib/src/clixon_xml_sort.c
@@ -338,7 +338,6 @@ xml_cmp_qsort(const void* arg1,
     return xml_cmp(*(struct xml**)arg1, *(struct xml**)arg2, 1);
 }
 
-
 /*! Sort children of an XML node 
  * Assume populated by yang spec.
  * @param[in] x0   XML node
@@ -615,7 +614,11 @@ xml_insert2(cxobj           *xp,
     }
     xc = xml_child_i(xp, mid);
     if ((yc = xml_spec(xc)) == NULL){
-	clicon_err(OE_XML, 0, "No spec found %s", xml_name(xc));	
+	if (xml_type(xc) != CX_ELMNT)
+	    clicon_err(OE_XML, 0, "No spec found %s (wrong xml type:%d)",
+		       xml_name(xc), xml_type(xc));	
+	else
+	    clicon_err(OE_XML, 0, "No spec found %s", xml_name(xc));	
 	goto done;
     }
     if (yc == yn){ /* Same yang */
diff --git a/test/test_augment.sh b/test/test_augment.sh
index ac2db916..27ba001b 100755
--- a/test/test_augment.sh
+++ b/test/test_augment.sh
@@ -6,7 +6,12 @@
 # both defined in the basic ietf-interfaces module (type) as well as the main
 # module through the augmented module ()
 # The ietf-interfaces is very restricted (not original).
-
+# From a namespace perspective, there are two modules, with symbols as follows:
+# 1. ietf-interface - urn:ietf:params:xml:ns:yang:ietf-interfaces
+#    interfaces, interface, name, type
+# 2. example-augment - urn:example:augment - mymod
+#    (augmented):     mandatory-leaf, me, other,
+#    (uses/grouping): ip, port, lid, lport
 # Magic line must be first in script (see README.md)
 s="$_" ; . ./lib.sh || if [ "$s" = $0 ]; then exit 0; else return 0; fi
 
@@ -175,7 +180,7 @@ expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></
   </interface></interfaces></config></edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf verify get with refined ports"
-expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface xmlns:mymod="urn:example:augment"><name>e1</name><type>mymod:some-new-iftype</type><mandatory-leaf>true</mandatory-leaf><port>80</port><lport>8080</lport></interface></interfaces></data></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface xmlns:mymod="urn:example:augment"><name>e1</name><type>mymod:some-new-iftype</type><mymod:mandatory-leaf>true</mymod:mandatory-leaf><mymod:port>80</mymod:port><mymod:lport>8080</mymod:lport></interface></interfaces></data></rpc-reply>]]>]]>$'
 
 new "netconf set identity defined in other"
 expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></target><config><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
@@ -183,7 +188,7 @@ expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></
     <name>e2</name>
     <type>fddi</type>
     <mymod:mandatory-leaf>true</mymod:mandatory-leaf>
-    <other>if:fddi</other>
+    <mymod:other>if:fddi</mymod:other>
   </interface></interfaces></config></edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf validate ok"
@@ -195,7 +200,7 @@ expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></
    <name>e3</name>
    <type>fddi</type>
    <mymod:mandatory-leaf>true</mymod:mandatory-leaf>
-   <me>mymod:you</me>
+   <mymod:me>mymod:you</mymod:me>
  </interface></interfaces></config></edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf commit ok"
@@ -203,11 +208,11 @@ expecteof "$clixon_netconf -qf $cfg" 0 "<rpc><commit/></rpc>]]>]]>" '^<rpc-reply
 
 # restconf and augment
 
-new "restconf get augment"
+new "restconf get augment json"
 expectpart "$(curl -s -i -X GET http://localhost/restconf/data/ietf-interfaces:interfaces)" 0 'HTTP/1.1 200 OK
' '{"ietf-interfaces:interfaces":{"interface":\[{"name":"e1","type":"example-augment:some-new-iftype","example-augment:mandatory-leaf":"true","example-augment:port":80,"example-augment:lport":8080},{"name":"e2","type":"fddi","example-augment:mandatory-leaf":"true","example-augment:other":"ietf-interfaces:fddi","example-augment:port":80,"example-augment:lport":8080},{"name":"e3","type":"fddi","example-augment:mandatory-leaf":"true","example-augment:me":"you","example-augment:port":80,"example-augment:lport":8080}\]}}
'
 
 new "restconf get augment xml"
-expectpart "$(curl -s -i -X GET -H 'Accept: application/yang-data+xml' http://localhost/restconf/data/ietf-interfaces:interfaces)" 0 'HTTP/1.1 200 OK
' '<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface xmlns:mymod="urn:example:augment"><name>e1</name><type>mymod:some-new-iftype</type><mandatory-leaf>true</mandatory-leaf><port>80</port><lport>8080</lport></interface><interface xmlns:mymod="urn:example:augment"><name>e2</name><type>fddi</type><mandatory-leaf>true</mandatory-leaf><other>if:fddi</other><port>80</port><lport>8080</lport></interface><interface xmlns:mymod="urn:example:augment"><name>e3</name><type>fddi</type><mandatory-leaf>true</mandatory-leaf><me>mymod:you</me><port>80</port><lport>8080</lport></interface></interfaces>'
+expectpart "$(curl -s -i -X GET -H 'Accept: application/yang-data+xml' http://localhost/restconf/data/ietf-interfaces:interfaces)" 0 'HTTP/1.1 200 OK
' '<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface xmlns:mymod="urn:example:augment"><name>e1</name><type>mymod:some-new-iftype</type><mymod:mandatory-leaf>true</mymod:mandatory-leaf><mymod:port>80</mymod:port><mymod:lport>8080</mymod:lport></interface><interface xmlns:mymod="urn:example:augment"><name>e2</name><type>fddi</type><mymod:mandatory-leaf>true</mymod:mandatory-leaf><mymod:other>if:fddi</mymod:other><mymod:port>80</mymod:port><mymod:lport>8080</mymod:lport></interface><interface xmlns:mymod="urn:example:augment"><name>e3</name><type>fddi</type><mymod:mandatory-leaf>true</mymod:mandatory-leaf><mymod:me>mymod:you</mymod:me><mymod:port>80</mymod:port><mymod:lport>8080</mymod:lport></interface></interfaces>'
 
 new "Kill restconf daemon"
 stop_restconf 
diff --git a/test/test_cli.sh b/test/test_cli.sh
index 8fd3dc35..52a24828 100755
--- a/test/test_cli.sh
+++ b/test/test_cli.sh
@@ -77,6 +77,7 @@ expectfn "$clixon_cli -1 -f $cfg -l o validate" 255 "Validate failed. Edit and t
 
 new "cli configure ip addr"
 expectfn "$clixon_cli -1 -f $cfg set interfaces interface eth/0/0 ipv4 address 1.2.3.4 prefix-length 24" 0 "^$"
+
 new "cli configure ip descr"
 expectfn "$clixon_cli -1 -f $cfg set interfaces interface eth/0/0 description mydesc" 0 "^$"
 new "cli configure ip type"
diff --git a/test/test_leafref.sh b/test/test_leafref.sh
index 8cc16293..fabad06b 100755
--- a/test/test_leafref.sh
+++ b/test/test_leafref.sh
@@ -56,10 +56,10 @@ module example{
              }
          }
          leaf address {
-             description "From RFC7950 9.9.5";
+             description "From RFC7950 9.9.6";
              type leafref {
                  path "../../if:interfaces/if:interface[if:name = current()/../relname]"
-                    + "/if:ipv4/if:address/if:ip";
+                    + "/ip:ipv4/ip:address/ip:ip";
             }
          }
          leaf wrong {
@@ -85,29 +85,29 @@ EOF
 
 BASEXML=$(cat <<EOF
 <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
-   <interface>
+   <interface xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip">
       <name>eth0</name>
       <type>ex:eth</type>
-      <ipv4>
-         <address>
-            <ip>192.0.2.1</ip>
-            <prefix-length>24</prefix-length>
-         </address>
-         <address>
-            <ip>192.0.2.2</ip>
-            <prefix-length>24</prefix-length>
-         </address>
-      </ipv4>
+      <ip:ipv4>
+         <ip:address>
+            <ip:ip>192.0.2.1</ip:ip>
+            <ip:prefix-length>24</ip:prefix-length>
+         </ip:address>
+         <ip:address>
+            <ip:ip>192.0.2.2</ip:ip>
+            <ip:prefix-length>24</ip:prefix-length>
+         </ip:address>
+      </ip:ipv4>
    </interface>
-   <interface>
+   <interface xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip">
       <name>lo</name>
       <type>ex:lo</type>
-      <ipv4>
-         <address>
-            <ip>127.0.0.1</ip>
-            <prefix-length>32</prefix-length>
-         </address>
-      </ipv4>
+      <ip:ipv4>
+         <ip:address>
+            <ip:ip>127.0.0.1</ip:ip>
+            <ip:prefix-length>32</ip:prefix-length>
+         </ip:address>
+      </ip:ipv4>
    </interface>
 </interfaces>
 EOF
diff --git a/test/test_netconf.sh b/test/test_netconf.sh
index 3604fa9c..b08d3af9 100755
--- a/test/test_netconf.sh
+++ b/test/test_netconf.sh
@@ -94,7 +94,7 @@ new "netconf discard-changes"
 expecteof "$clixon_netconf -qf $cfg" 0 "<rpc><discard-changes/></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf edit config"
-expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></target><config><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface><name>eth/0/0</name></interface><interface><name>eth1</name><enabled>true</enabled><ipv4><address><ip>9.2.3.4</ip><prefix-length>24</prefix-length></address></ipv4></interface></interfaces></config></edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
+expecteof "$clixon_netconf -qf $cfg" 0 '<rpc><edit-config><target><candidate/></target><config><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface><name>eth/0/0</name></interface><interface xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip"><name>eth1</name><enabled>true</enabled><ip:ipv4><ip:address><ip:ip>9.2.3.4</ip:ip><ip:prefix-length>24</ip:prefix-length></ip:address></ip:ipv4></interface></interfaces></config></edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 # Too many quotes
 cat <<EOF > $tmp # new
@@ -102,7 +102,7 @@ cat <<EOF > $tmp # new
 EOF
 
 new "netconf get config xpath"
-expecteof "$clixon_netconf -qf $cfg" 0 "$(cat $tmp)" '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface><name>eth1</name><enabled>true</enabled></interface></interfaces></data></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $cfg" 0 "$(cat $tmp)" '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip"><name>eth1</name><enabled>true</enabled></interface></interfaces></data></rpc-reply>]]>]]>$'
 
 # Too many quotes
 cat <<EOF > $tmp # new
@@ -110,7 +110,7 @@ cat <<EOF > $tmp # new
 EOF
 
 new "netconf get config xpath parent"
-expecteof "$clixon_netconf -qf $cfg" 0 "$(cat $tmp)" '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface><name>eth/0/0</name><enabled>true</enabled></interface><interface><name>eth1</name><enabled>true</enabled><ipv4><enabled>true</enabled><forwarding>false</forwarding><address><ip>9.2.3.4</ip><prefix-length>24</prefix-length></address></ipv4></interface></interfaces></data></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $cfg" 0 "$(cat $tmp)" '^<rpc-reply><data><interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"><interface><name>eth/0/0</name><enabled>true</enabled></interface><interface xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip"><name>eth1</name><enabled>true</enabled><ip:ipv4><ip:enabled>true</ip:enabled><ip:forwarding>false</ip:forwarding><ip:address><ip:ip>9.2.3.4</ip:ip><ip:prefix-length>24</ip:prefix-length></ip:address></ip:ipv4></interface></interfaces></data></rpc-reply>]]>]]>$'
 
 new "netconf validate missing type"
 expecteof "$clixon_netconf -qf $cfg" 0 "<rpc><validate><source><candidate/></source></validate></rpc>]]>]]>" "^<rpc-reply><rpc-error>"
diff --git a/test/test_restconf_err.sh b/test/test_restconf_err.sh
index c62eb413..d6729d31 100755
--- a/test/test_restconf_err.sh
+++ b/test/test_restconf_err.sh
@@ -11,7 +11,10 @@
 # usually contain a payload that represents the error condition, such
 # that it describes the error state and what next steps are suggested
 # for resolving it.
-
+#
+# Note this is different from an api-path that is invalid from a yang point
+# of view, this is interpreted as 400 Bad Request invalid-value/unknown-element
+# XXX: complete non-existent yang with unknown-element for all PUT/POST/GET api-paths
 
 # Magic line must be first in script (see README.md)
 s="$_" ; . ./lib.sh || if [ "$s" = $0 ]; then exit 0; else return 0; fi
@@ -20,7 +23,7 @@ APPNAME=example
 
 cfg=$dir/conf.xml
 fyang=$dir/example.yang
-fyang2=$dir/aug.yang
+fyang2=$dir/augment.yang
 fxml=$dir/initial.xml
 
 #  <CLICON_YANG_MODULE_MAIN>example</CLICON_YANG_MODULE_MAIN>
@@ -34,15 +37,24 @@ cat <<EOF > $cfg
   <CLICON_SOCK>/usr/local/var/$APPNAME/$APPNAME.sock</CLICON_SOCK>
   <CLICON_BACKEND_PIDFILE>$dir/restconf.pidfile</CLICON_BACKEND_PIDFILE>
   <CLICON_XMLDB_DIR>/usr/local/var/$APPNAME</CLICON_XMLDB_DIR>
+  <CLICON_CLISPEC_DIR>/usr/local/lib/$APPNAME/clispec</CLICON_CLISPEC_DIR>
+  <CLICON_CLI_DIR>/usr/local/lib/$APPNAME/cli</CLICON_CLI_DIR>
+  <CLICON_CLI_MODE>$APPNAME</CLICON_CLI_MODE>
 </clixon-config>
 EOF
 
 cat <<EOF > $fyang2
-module augm{
+module augment{
    yang-version 1.1;
    namespace "urn:example:aug";
    prefix aug;
    description "Used as a base for augment";
+   container route-config {
+	description
+	    "Root container for routing models";
+	container dynamic {
+	}
+   }
    container route-state {
 	description
 	    "Root container for routing models";
@@ -58,7 +70,7 @@ module example{
    yang-version 1.1;
    namespace "urn:example:clixon";
    prefix ex;
-   import aug {
+   import augment {
         description "Just for augment";
 	prefix "aug";
    }
@@ -86,12 +98,15 @@ module example{
    }
    augment "/aug:route-config/aug:dynamic" {
       container ospf {
-         container routers {
-	    container auto-cost {
-            	leaf reference-bandwidth {
-			    type uint32;
-                }
-            }
+         leaf reference-bandwidth {
+	    type uint32;
+         }
+      }
+   }
+   augment "/aug:route-config/aug:dynamic" {
+      container ospf {
+         leaf reference-bandwidth {
+	    type uint32;
          }
       }
    }
@@ -147,13 +162,28 @@ if false; then
 new "restconf POST non-existent (no yang) element"
 # should be invalid element
 expectpart "$(curl -is -X POST -H 'Content-Type: application/yang-data+xml' -d "$XML" http://localhost/restconf/data/example:a=23/xxx)" 0 'HTTP/1.1 400 Bad Request' '{"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"invalid-value","error-severity":"error","error-message":"Unknown element: '
-
-
-new "restconf GET multi-namespace path"
-# simplify yang
-# works for config?
-expectpart "$(curl -si -X GET http://localhost/restconf/data/augm:route-state/dynamic/ospf/routers/auto-cost/reference-bandwidth)" 0 'HTTP/1.1 404 Not Found' '{"ietf-restconf:errors":{"error":{"rpc-error":{"error-type":"application","error-tag":"invalid-value","error-severity":"error","error-message":"Unknown element: 'xxx'"}}}}'
 fi
+
+# Test for multi-module path where an augment stretches across modules
+new "restconf POST augment multi-namespace path"
+expecteq "$(curl -s -X POST -H 'Content-Type: application/yang-data+xml' -d '<route-config xmlns="urn:example:aug"><dynamic><ospf xmlns="urn:example:clixon"><reference-bandwidth>23</reference-bandwidth></ospf></dynamic></route-config>' http://localhost/restconf/data)" 0 ''
+
+new "restconf GET augment multi-namespace top"
+expectpart "$(curl -si -X GET http://localhost/restconf/data/augment:route-config)" 0 'HTTP/1.1 200 OK' '{"augment:route-config":{"dynamic":{"example:ospf":{"reference-bandwidth":23}}}}'
+
+new "restconf GET augment multi-namespace level 1"
+expectpart "$(curl -si -X GET http://localhost/restconf/data/augment:route-config/dynamic)" 0 'HTTP/1.1 200 OK' '{"augment:dynamic":{"example:ospf":{"reference-bandwidth":23}}}'
+
+new "restconf GET augment multi-namespace cross"
+expectpart "$(curl -si -X GET http://localhost/restconf/data/augment:route-config/dynamic/example:ospf)" 0 'HTTP/1.1 200 OK' '{"example:ospf":{"reference-bandwidth":23}}'
+
+new "restconf GET augment multi-namespace cross level 2"
+expectpart "$(curl -si -X GET http://localhost/restconf/data/augment:route-config/dynamic/example:ospf/reference-bandwidth)" 0 'HTTP/1.1 200 OK' '{"example:reference-bandwidth":23}'
+
+# XXX actually no such element
+#new "restconf GET augment multi-namespace, no 2nd module in api-path, fail"
+#expectpart "$(curl -si -X GET http://localhost/restconf/data/augment:route-config/dynamic/ospf)" 0 'HTTP/1.1 404 Not Found' '{"ietf-restconf:errors":{"error":{"rpc-error":{"error-type":"application","error-tag":"invalid-value","error-severity":"error","error-message":"Instance does not exist"}}}}'
+
 new "Kill restconf daemon"
 stop_restconf