diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c548fb7..11a7b845 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -50,6 +50,7 @@
 ```
 
 ### Minor changes
+* Added CLICON_NACM_MODE "internal-rpc" which is for RPC functionality only, ie no module or data-node read-write functionality. This is for backward compatibility with Clixon 3. (A reduced-functionality "internal")
 * Made Makefile concurrent so that it can be compiled with -jN
 * Added flags to example backend to control its behaviour:
   * Start with `-- -r` to run the reset plugin
@@ -68,7 +69,7 @@
 * Added libgen.h for baseline()
 	
 ### Corrected Bugs
-* Re-inserted `cli_output_reset` for what was erroneuos thought to be an obsolete function (
+* Re-inserted `cli_output_reset` for what was erroneuos thought to be an obsolete function
   * See in 3.9.0 minro changes: Replaced all calls to (obsolete) `cli_output` with `fprintf`
 * Allowed Yang extended Xpath functions (syntax only):
   * re-match, deref, derived-from, derived-from-or-self, enum-value, bit-is-set
diff --git a/apps/backend/backend_client.c b/apps/backend/backend_client.c
index 49420687..feba64f5 100644
--- a/apps/backend/backend_client.c
+++ b/apps/backend/backend_client.c
@@ -321,7 +321,7 @@ from_client_get_config(clicon_handle h,
 	goto ok;
     }
     /* Pre-NACM access step */
-    if ((ret = nacm_access_pre(h, username, &xnacm)) < 0)
+    if ((ret = nacm_access_pre(h, username, NACM_DATA, &xnacm)) < 0)
 	goto done;
     if (ret == 0){ /* Do NACM validation */
 	if (xpath_vec(xret, "%s", &xvec, &xlen, xpath?xpath:"/") < 0)
@@ -790,7 +790,7 @@ from_client_get(clicon_handle h,
 	goto ok;
     }
     /* Pre-NACM access step */
-    if ((ret = nacm_access_pre(h, username, &xnacm)) < 0)
+    if ((ret = nacm_access_pre(h, username, NACM_DATA, &xnacm)) < 0)
 	goto done;
     if (ret == 0){ /* Do NACM validation */
 	if (xpath_vec(xret, "%s", &xvec, &xlen, xpath?xpath:"/") < 0)
@@ -1114,7 +1114,7 @@ from_client_msg(clicon_handle        h,
 	clicon_debug(1, "%s module:%s rpc:%s", __FUNCTION__, module, rpc);
 	/* Pre-NACM access step */
 	xnacm = NULL;
-	if ((ret = nacm_access_pre(h, username, &xnacm)) < 0)
+	if ((ret = nacm_access_pre(h, username, NACM_RPC, &xnacm)) < 0)
 	    goto done;
 	if (ret == 0){ /* Do NACM validation */
 	    /* NACM rpc operation exec validation */
diff --git a/lib/clixon/clixon_nacm.h b/lib/clixon/clixon_nacm.h
index 4b016dd5..83997de6 100644
--- a/lib/clixon/clixon_nacm.h
+++ b/lib/clixon/clixon_nacm.h
@@ -60,6 +60,17 @@ enum nacm_access{
     NACM_DELETE,
     NACM_EXEC
 };
+
+/*! In RFC8341, NACM defines three access points: rpc 
+ * 3.4.4  Incoming RPC Message Validation
+ * 3.4.5  Data Node Access Validation
+ * 3.4.6  Outgoing <notification> Authorization
+ */
+enum nacm_point {
+    NACM_RPC,
+    NACM_DATA,
+    NACM_NOTIFICATION,
+};
 /*
  * Prototypes
  */
@@ -67,7 +78,7 @@ int nacm_rpc(char *rpc, char *module, char *username, cxobj *xnacm, cbuf *cbret)
 int nacm_datanode_read(cxobj *xt, cxobj **xvec, size_t xlen, char *username, cxobj *nacm_xtree);
 int nacm_datanode_write(cxobj *xt, cxobj *xr, enum nacm_access access,
 			char *username, cxobj *xnacm, cbuf *cbret);
-int nacm_access_pre(clicon_handle h, char *username, cxobj **xnacmp);
+int nacm_access_pre(clicon_handle h, char *username, enum nacm_point point, cxobj **xnacmp);
 int nacm_access(char *mode, cxobj *xnacmin, char *username);
 
 #endif /* _CLIXON_NACM_H */
diff --git a/lib/src/clixon_nacm.c b/lib/src/clixon_nacm.c
index 6f53d88f..6e95cbbe 100644
--- a/lib/src/clixon_nacm.c
+++ b/lib/src/clixon_nacm.c
@@ -808,7 +808,7 @@ nacm_access(char          *mode,
 	goto permit;
     /* 0. If nacm-mode is external, get NACM defintion from separet tree,
        otherwise get it from internal configuration */
-    if (strcmp(mode, "external") && strcmp(mode, "internal")){
+    if (strcmp(mode, "external") && strcmp(mode, "internal") && strcmp(mode, "internal-rpc")){
 	clicon_err(OE_XML, 0, "Invalid NACM mode: %s", mode);
 	goto done;
     }
@@ -846,6 +846,7 @@ nacm_access(char          *mode,
  * etc. If retval = 1 access is OK and skip next NACM step.
  * @param[in]  h        Clicon handle
  * @param[in]  username User name of requestor
+ * @param[in]  point  NACM access control point
  * @param[out] xncam    NACM XML tree, set if retval=0. Free after use
  * @retval -1  Error
  * @retval  0  OK but not validated. Need to do NACM step using xnacm
@@ -864,6 +865,7 @@ nacm_access(char          *mode,
 int
 nacm_access_pre(clicon_handle  h,
 		char          *username,
+		enum nacm_point point,
 		cxobj        **xnacmp)
 {
     int    retval = -1;
@@ -882,6 +884,15 @@ nacm_access_pre(clicon_handle  h,
 	    if (xmldb_get(h, "running", "nacm", 0, &xnacm0, NULL) < 0)
 		goto done;
 	}
+	else if (strcmp(mode, "internal-rpc")==0){
+	    /* Special mode only implemet exec rpc access point */
+	    if (point == NACM_RPC){
+		if (xmldb_get(h, "running", "nacm", 0, &xnacm0, NULL) < 0)
+		    goto done;
+	    }
+	    else
+		goto permit;
+	}
     }
     /* If config does not exist then the operation is permitted(?) */
     if (xnacm0 == NULL)
diff --git a/yang/clixon/clixon-config@2019-03-05.yang b/yang/clixon/clixon-config@2019-03-05.yang
index bbf62324..99b3eaad 100644
--- a/yang/clixon/clixon-config@2019-03-05.yang
+++ b/yang/clixon/clixon-config@2019-03-05.yang
@@ -121,6 +121,13 @@ module clixon-config {
 	    enum internal{
 		description "NACM is enabled and available in the regular config";
 	    }
+	    enum internal-rpc{
+		description
+		   "NACM is enabled and available in the regular config. 
+                    But only for RPC functionality, ie no module or data-node
+                    read-write functionality. 
+                    This is for backward compatibility with Clixon 3.8.";
+	    }
 	    enum external{
 		description "NACM is enabled and available in a separate config";
 	    }