diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0d23695a..308c0786 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -51,6 +51,11 @@ Expected: July 2020
 
 ### C/CLI-API changes on existing features (For developers)
 
+* Changed module-specific upgrade API, not backward compatible. The API has been simplified which means more has to be done by the programmer.
+  * In summary, a user registers an upgrade callback per module. The callback is called at startup if the module is added, has been removed or if the revision on file is different from the one in the system. 
+  * The register function has removed `from` and `rev` parameters: `upgrade_callback_register(h, cb, namespace, arg)`
+  * The callback function has a new `op` parameter with possible values: `XML_FLAG_ADD`, `XML_FLAG_CHANGE` or `XML_FLAG_CHANGE`: `clicon_upgrade_cb(h, xn, ns, op, from, to, arg, cbret)`
+
 * Added new cli show functions to work with cligen_output for cligen pageing to work. To achieve this, replace function calls as follows:
   * xml2txt(...) --> xml2txt_cb(..., cligen_output)
   * xml2cli(...) --> xml2cli_cb(..., cligen_output)
diff --git a/apps/backend/backend_commit.c b/apps/backend/backend_commit.c
index 823eb878..f1e16882 100644
--- a/apps/backend/backend_commit.c
+++ b/apps/backend/backend_commit.c
@@ -177,19 +177,19 @@ startup_common(clicon_handle       h,
     int                 retval = -1;
     yang_stmt          *yspec;
     int                 ret;
-    modstate_diff_t    *msd = NULL;
+    modstate_diff_t    *msdiff = NULL;
     cxobj              *xt = NULL;
     cxobj              *x;
     cxobj              *xret = NULL;
     
     /* If CLICON_XMLDB_MODSTATE is enabled, then get the db XML with 
-     * potentially non-matching module-state in msd
+     * potentially non-matching module-state in msdiff
      */
     if (clicon_option_bool(h, "CLICON_XMLDB_MODSTATE"))
-	if ((msd = modstate_diff_new()) == NULL)
+	if ((msdiff = modstate_diff_new()) == NULL)
 	    goto done;
     clicon_debug(1, "Reading startup config from %s", db);
-    if (xmldb_get0(h, db, NULL, "/", 0, &xt, msd) < 0)
+    if (xmldb_get0(h, db, NULL, "/", 0, &xt, msdiff) < 0)
 	goto done;
     clicon_debug(1, "Reading startup config done");
     /* Clear flags xpath for get */
@@ -202,13 +202,15 @@ startup_common(clicon_handle       h,
     }
     /* Here xt is old syntax */
     /* General purpose datastore upgrade */
-    if (clixon_plugin_datastore_upgrade_all(h, db, xt, msd) < 0)
+    if (clixon_plugin_datastore_upgrade_all(h, db, xt, msdiff) < 0)
        goto done;
     /* Module-specific upgrade callbacks */
-    if ((ret = clixon_module_upgrade(h, xt, msd, cbret)) < 0)
-       goto done;
-    if (ret == 0)
-       goto fail;
+    if (msdiff){
+	if ((ret = clixon_module_upgrade(h, xt, msdiff, cbret)) < 0)
+	    goto done;
+	if (ret == 0)
+	    goto fail;
+    }
     if ((yspec = clicon_dbspec_yang(h)) == NULL){
 	clicon_err(OE_YANG, 0, "Yang spec not set");
 	goto done;
@@ -257,8 +259,8 @@ startup_common(clicon_handle       h,
 	xml_free(xret);
     if (xt)
 	xml_free(xt);
-    if (msd)
-	modstate_diff_free(msd);
+    if (msdiff)
+	modstate_diff_free(msdiff);
     return retval;
  fail: 
     retval = 0;
diff --git a/example/main/example_backend.c b/example/main/example_backend.c
index 7996fb53..86d78ebc 100644
--- a/example/main/example_backend.c
+++ b/example/main/example_backend.c
@@ -535,9 +535,9 @@ static const map_str2str namespace_map[] = {
  */
 int
 example_upgrade(clicon_handle    h,
-               char            *db,
-               cxobj           *xt,
-               modstate_diff_t *msd)
+		char            *db,
+		cxobj           *xt,
+		modstate_diff_t *msd)
 {
     int                       retval = -1;
     cvec                     *nsc = NULL;    /* Canonical namespace */
@@ -616,16 +616,17 @@ example_upgrade(clicon_handle    h,
  * @param[in]  h       Clicon handle 
  * @param[in]  xn      XML tree to be updated
  * @param[in]  ns      Namespace of module (for info)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
  * @param[in]  from    From revision on the form YYYYMMDD
  * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
  * @param[in]  arg     User argument given at rpc_callback_register() 
- * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error.. 
+ * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error..  if retval = 0
  * @retval     1       OK
  * @retval     0       Invalid
  * @retval    -1       Error
  * @see clicon_upgrade_cb
  * @see test_upgrade_interfaces.sh
- * @see upgrade_2016
+ * @see upgrade_2014_to_2016
  * This example shows a two-step upgrade where the 2014 function does:
  * - Move /if:interfaces-state/if:interface/if:admin-status to 
  *        /if:interfaces/if:interface/
@@ -634,13 +635,14 @@ example_upgrade(clicon_handle    h,
  * - Rename /interfaces/interface/description to descr 
  */
 static int
-upgrade_2016(clicon_handle h,       
-	     cxobj        *xt,      
-	     char         *ns,
-	     uint32_t      from,
-	     uint32_t      to,
-	     void         *arg,     
-	     cbuf         *cbret)
+upgrade_2014_to_2016(clicon_handle h,       
+		     cxobj        *xt,      
+		     char         *ns,
+		     uint16_t      op,
+		     uint32_t      from,
+		     uint32_t      to,
+		     void         *arg,     
+		     cbuf         *cbret)
 {
     int        retval = -1;
     yang_stmt *yspec;
@@ -654,6 +656,7 @@ upgrade_2016(clicon_handle h,
     int        i;
     char      *name;
 
+    clicon_debug(1, "%s from:%d to:%d", __FUNCTION__, from, to);
     /* Get Yang module for this namespace. Note it may not exist (if obsolete) */
     yspec = clicon_dbspec_yang(h);	
     if ((ym = yang_find_module_by_namespace(yspec, ns)) == NULL)
@@ -716,16 +719,17 @@ upgrade_2016(clicon_handle h,
  * @param[in]  h       Clicon handle 
  * @param[in]  xn      XML tree to be updated
  * @param[in]  ns      Namespace of module (for info)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
  * @param[in]  from    From revision on the form YYYYMMDD
  * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
  * @param[in]  arg     User argument given at rpc_callback_register() 
- * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error.. 
+ * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error..  if retval = 0
  * @retval     1       OK
  * @retval     0       Invalid
  * @retval    -1       Error
  * @see clicon_upgrade_cb
  * @see test_upgrade_interfaces.sh
- * @see upgrade_2016
+ * @see upgrade_2016_to_2018
  * The 2016 function does:
  * - Delete /if:interfaces-state
  * - Wrap /interfaces/interface/descr to /interfaces/interface/docs/descr
@@ -733,13 +737,14 @@ upgrade_2016(clicon_handle h,
  *   fraction-digits 3 and divide all values with 1000
  */
 static int
-upgrade_2018(clicon_handle h,       
-	     cxobj        *xt,      
-	     char         *ns,
-	     uint32_t      from,
-	     uint32_t      to,
-	     void         *arg,     
-	     cbuf         *cbret)
+upgrade_2016_to_2018(clicon_handle h,       
+		     cxobj        *xt,      
+		     char         *ns,
+		     uint16_t      op,
+		     uint32_t      from,
+		     uint32_t      to,
+		     void         *arg,     
+		     cbuf         *cbret)
 {
     int        retval = -1;
     yang_stmt *yspec;
@@ -752,6 +757,7 @@ upgrade_2018(clicon_handle h,
     size_t     vlen;
     int        i;
 
+    clicon_debug(1, "%s from:%d to:%d", __FUNCTION__, from, to);
     /* Get Yang module for this namespace. Note it may not exist (if obsolete) */
     yspec = clicon_dbspec_yang(h);	
     if ((ym = yang_find_module_by_namespace(yspec, ns)) == NULL)
@@ -800,6 +806,58 @@ upgrade_2018(clicon_handle h,
     return retval;
 }
 
+/*! Testcase module-specific upgrade function moving interfaces-state to interfaces
+ * @param[in]  h       Clicon handle 
+ * @param[in]  xn      XML tree to be updated
+ * @param[in]  ns      Namespace of module (for info)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
+ * @param[in]  from    From revision on the form YYYYMMDD
+ * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
+ * @param[in]  arg     User argument given at rpc_callback_register() 
+ * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error..  if retval = 0
+ * @retval     1       OK
+ * @retval     0       Invalid
+ * @retval    -1       Error
+ * @see clicon_upgrade_cb
+ * @see test_upgrade_interfaces.sh
+ * @see upgrade_2014_to_2016
+ * This example shows a two-step upgrade where the 2014 function does:
+ * - Move /if:interfaces-state/if:interface/if:admin-status to 
+ *        /if:interfaces/if:interface/
+ * - Move /if:interfaces-state/if:interface/if:statistics to
+ *        /if:interfaces/if:interface/
+ * - Rename /interfaces/interface/description to descr 
+ */
+static int
+upgrade_interfaces(clicon_handle h,       
+		   cxobj        *xt,      
+		   char         *ns,
+		   uint16_t      op,
+		   uint32_t      from,
+		   uint32_t      to,
+		   void         *arg,     
+		   cbuf         *cbret)
+{
+    int retval = -1;
+
+    if (from <= 20140508){
+	if ((retval = upgrade_2014_to_2016(h, xt, ns, op, from, to, arg, cbret)) < 0)
+	    goto done;
+	if (retval == 0)
+	    goto done;
+    }
+    if (from <= 20160101){
+    	if ((retval = upgrade_2016_to_2018(h, xt, ns, op, from, to, arg, cbret)) < 0)
+	    goto done;
+	if (retval == 0)
+	    goto done;
+    }
+    // ok:
+    retval = 1;
+ done:
+    return retval;
+}
+
 /*! Plugin state reset. Add xml or set state in backend machine.
  * Called in each backend plugin. plugin_reset is called after all plugins
  * have been initialized. This give the application a chance to reset
@@ -1026,13 +1084,18 @@ clixon_plugin_init(clicon_handle h)
      * test interface example. Otherwise the auto-upgrade feature is enabled.
      */
     if (_module_upgrade){
-	if (upgrade_callback_register(h, upgrade_2016, "urn:example:interfaces", 20140508, 20160101, NULL) < 0)
+#if 1
+	if (upgrade_callback_register(h, upgrade_interfaces, "urn:example:interfaces", NULL) < 0)
 	    goto done;
-	if (upgrade_callback_register(h, upgrade_2018, "urn:example:interfaces", 20160101, 20180220, NULL) < 0)
+#else
+	if (upgrade_callback_register(h, upgrade_2014_to_2016, "urn:example:interfaces", NULL) < 0)
 	    goto done;
+	if (upgrade_callback_register(h, upgrade_2016_to_2018, "urn:example:interfaces", NULL) < 0)
+	    goto done;
+#endif
     }
     else
-	if (upgrade_callback_register(h, xml_changelog_upgrade, NULL, 0, 0, NULL) < 0)
+	if (upgrade_callback_register(h, xml_changelog_upgrade, NULL, NULL) < 0)
 	    goto done;
 
     /* Return plugin API */
diff --git a/lib/clixon/clixon_plugin.h b/lib/clixon/clixon_plugin.h
index d1565209..a35ffe36 100644
--- a/lib/clixon/clixon_plugin.h
+++ b/lib/clixon/clixon_plugin.h
@@ -45,7 +45,7 @@
 /* Hardcoded plugin symbol. Must exist in all plugins to kickstart 
  * @see clixon_plugin_init
  */
-#define CLIXON_PLUGIN_INIT     "clixon_plugin_init" 
+#define CLIXON_PLUGIN_INIT     "clixon_plugin_init"
 
 /*
  * Types
@@ -72,10 +72,11 @@ typedef int (*clicon_rpc_cb)(
  * @param[in]  h       Clicon handle 
  * @param[in]  xn      XML tree to be updated
  * @param[in]  namespace Namespace of module
- * @param[in]  from    From revision on the form YYYYMMDD
- * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
+ * @param[in]  from    From revision on the form YYYYMMDD (if DEL or CHANGE)
+ * @param[in]  to      To revision on the form YYYYMMDD (if ADD or CHANGE)
  * @param[in]  arg     User argument given at rpc_callback_register() 
- * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error.. 
+ * @param[out] cbret   Return xml tree, eg <rpc-reply>..., <rpc-error..  (if retval = 0)
  * @retval     1       OK
  * @retval     0       Invalid
  * @retval    -1       Error
@@ -84,6 +85,7 @@ typedef int (*clicon_upgrade_cb)(
     clicon_handle h,       
     cxobj        *xn,      
     char         *namespace,
+    uint16_t      op,
     uint32_t      from,
     uint32_t      to,
     void         *arg,     
@@ -253,7 +255,7 @@ struct clixon_plugin_api{
 /*
  * Macros
  */
-#define upgrade_callback_register(h, cb, namespace, from, rev, arg) upgrade_callback_reg_fn((h), (cb), #cb, (namespace), (from), (rev), (arg))
+#define upgrade_callback_register(h, cb, namespace, arg) upgrade_callback_reg_fn((h), (cb), #cb, (namespace), (arg))
 
 typedef struct clixon_plugin_api clixon_plugin_api;
 
@@ -309,8 +311,8 @@ int rpc_callback_delete_all(clicon_handle h);
 int rpc_callback_call(clicon_handle h, cxobj *xe, cbuf *cbret, void *arg);
 
 /* upgrade callback API */
-int upgrade_callback_reg_fn(clicon_handle h, clicon_upgrade_cb cb, const char *strfn, char *namespace, uint32_t from, uint32_t to, void *arg);
+int upgrade_callback_reg_fn(clicon_handle h, clicon_upgrade_cb cb, const char *strfn, char *namespace, void *arg);
 int upgrade_callback_delete_all(clicon_handle h);
-int upgrade_callback_call(clicon_handle h, cxobj *xt, char *namespace, uint32_t from, uint32_t to, cbuf *cbret);
+int upgrade_callback_call(clicon_handle h, cxobj *xt, char *namespace, uint16_t op, uint32_t from, uint32_t to, cbuf *cbret);
 
 #endif  /* _CLIXON_PLUGIN_H_ */
diff --git a/lib/clixon/clixon_xml_changelog.h b/lib/clixon/clixon_xml_changelog.h
index 587478df..c5251bb0 100644
--- a/lib/clixon/clixon_xml_changelog.h
+++ b/lib/clixon/clixon_xml_changelog.h
@@ -40,7 +40,7 @@
 /*
  * Prototypes
  */
-int xml_changelog_upgrade(clicon_handle h, cxobj *xn, char *namespace, uint32_t from, uint32_t to, void *arg, cbuf *cbret);
+int xml_changelog_upgrade(clicon_handle h, cxobj *xn, char *namespace, uint16_t op, uint32_t from, uint32_t to, void *arg, cbuf *cbret);
 int clixon_xml_changelog_init(clicon_handle h);
 int xml_namespace_vec(clicon_handle h, cxobj *xt, char *namespace, cxobj ***vec, size_t *veclen);
 
diff --git a/lib/clixon/clixon_yang_module.h b/lib/clixon/clixon_yang_module.h
index 178d4b0a..977a84ed 100644
--- a/lib/clixon/clixon_yang_module.h
+++ b/lib/clixon/clixon_yang_module.h
@@ -54,8 +54,7 @@
 typedef struct {
     int    md_status; /* 0 if no module-state in a datastore, 1 if there is */
     char  *md_set_id; /* server-specific identifier */
-    cxobj *md_del;    /* yang module state deletes */
-    cxobj *md_mod;    /* yang module state modifications */
+    cxobj *md_diff;  /* yang module state containing revisions and XML_FLAG_ADD|DEL|CHANGE */
 } modstate_diff_t;
 
 /*
diff --git a/lib/src/clixon_datastore_read.c b/lib/src/clixon_datastore_read.c
index ac364a9d..69f616f3 100644
--- a/lib/src/clixon_datastore_read.c
+++ b/lib/src/clixon_datastore_read.c
@@ -212,92 +212,111 @@ xml_copy_marked(cxobj *x0,
 
 /*! Read module-state in an XML tree
  *
- * @param[in]  th    Datastore text handle
- * @param[in]  yspec Top-level yang spec 
- * @param[in]  xt    XML tree
- * @param[out] msd   If set, return modules-state differences
+ * @param[in]  th     Datastore text handle
+ * @param[in]  yspec  Top-level yang spec 
+ * @param[in]  xt     XML tree
+ * @param[out] msdiff Modules-state differences
  *
+ * The modstate difference contains:
+ * - if there is a modstate
+ * - the modstate identifier
+ * - An entry for each modstate that differs marked with flag: ADD|DEL|CHANGE
+ *
+ * Algorithm:
  * Read mst (module-state-tree) from xml tree (if any) and compare it with 
  * the system state mst.
  * This can happen:
  * 1) There is no modules-state info in the file
  * 2) There is module state info in the file
  * 3) For each module state m in the file:
- *    3a) There is no such module in the system
+ *    3a) There is no such module in the system -> add to list mark as DEL
  *    3b) File module-state matches system
- *    3c) File module-state does not match system
+ *    3c) File module-state does not match system -> add to list mark as CHANGE
+ * 4) For each module state s in the system
+ *    4a) If there is no such module in the file -> add to list mark as ADD
  */
 static int
 text_read_modstate(clicon_handle       h,
 		   yang_stmt          *yspec,
 		   cxobj              *xt,
-		   modstate_diff_t    *msd)
+		   modstate_diff_t    *msdiff)
 {
     int    retval = -1;
-    cxobj *xmodst;
-    cxobj *xm = NULL;
-    cxobj *xm2;
-    cxobj *xs;
-    char  *name; /* module name */
-    char  *mrev; /* file revision */
-    char  *srev; /* system revision */
-    cxobj *xmcache = NULL;
+    cxobj *xmodfile = NULL;   /* modstate of system (loaded yang modules in runtime) */
+    cxobj *xmodsystem = NULL; /* modstate of file, eg startup */
+    cxobj *xf = NULL;         /* xml modstate in file */
+    cxobj *xf2;               /* copy */
+    cxobj *xs;                /* xml modstate in system */
+    cxobj *xs2;               /* copy */
+    char  *name;              /* module name */
+    char  *frev;              /* file revision */
+    char  *srev;              /* system revision */
 
-    xmcache = clicon_modst_cache_get(h, 1);
-    if ((xmodst = xml_find_type(xt, NULL, "modules-state", CX_ELMNT)) == NULL){
+    /* Read module-state as computed at startup, see startup_module_state() */
+    xmodsystem = clicon_modst_cache_get(h, 1);
+    if ((xmodfile = xml_find_type(xt, NULL, "modules-state", CX_ELMNT)) == NULL){
 	/* 1) There is no modules-state info in the file */
     }
-    else if (xmcache && msd){
-	msd->md_status = 1;  /* There is module state in the file */
-	/* Create diff trees */
+    else if (xmodsystem && msdiff){
+	msdiff->md_status = 1;  /* There is module state in the file */
+	/* Create modstate tree for this file */
 	if (clixon_xml_parse_string("<modules-state xmlns=\"urn:ietf:params:xml:ns:yang:ietf-yang-library\"/>",
-				    YB_MODULE, yspec, &msd->md_del, NULL) < 0)
+				    YB_MODULE, yspec, &msdiff->md_diff, NULL) < 0)
 	    goto done;
-	if (xml_rootchild(msd->md_del, 0, &msd->md_del) < 0) 
-	    goto done;
-	if (clixon_xml_parse_string("<modules-state xmlns=\"urn:ietf:params:xml:ns:yang:ietf-yang-library\"/>",
-				    YB_MODULE, yspec, &msd->md_mod, NULL) < 0)
-	    goto done;
-	if (xml_rootchild(msd->md_mod, 0, &msd->md_mod) < 0) 
+	if (xml_rootchild(msdiff->md_diff, 0, &msdiff->md_diff) < 0) 
 	    goto done;
 
 	/* 3) For each module state m in the file */
-	while ((xm = xml_child_each(xmodst, xm, CX_ELMNT)) != NULL) {
-	    if (strcmp(xml_name(xm), "module-set-id") == 0){
-		if (xml_body(xm) && (msd->md_set_id = strdup(xml_body(xm))) == NULL){
+	xf = NULL;
+	while ((xf = xml_child_each(xmodfile, xf, CX_ELMNT)) != NULL) {
+	    if (strcmp(xml_name(xf), "module-set-id") == 0){
+		if (xml_body(xf) && (msdiff->md_set_id = strdup(xml_body(xf))) == NULL){
 		    clicon_err(OE_UNIX, errno, "strdup");
 		    goto done;
 		}
 	    }
-	    if (strcmp(xml_name(xm), "module"))
+	    if (strcmp(xml_name(xf), "module"))
 		continue; /* ignore other tags, such as module-set-id */
-	    if ((name = xml_find_body(xm, "name")) == NULL)
+	    if ((name = xml_find_body(xf, "name")) == NULL)
 		continue;
 	    /* 3a) There is no such module in the system */
-	    if ((xs = xpath_first(xmcache, NULL, "module[name=\"%s\"]", name)) == NULL){
-		//		fprintf(stderr, "%s: Module %s: not in system\n", __FUNCTION__, name);
-		if ((xm2 = xml_dup(xm)) == NULL)
+	    if ((xs = xpath_first(xmodsystem, NULL, "module[name=\"%s\"]", name)) == NULL){
+		if ((xf2 = xml_dup(xf)) == NULL) 	  /* Make a copy of this modstate */
 		    goto done;
-		if (xml_addsub(msd->md_del, xm2) < 0)
+		if (xml_addsub(msdiff->md_diff, xf2) < 0)   /* Add it to modstatediff */
 		    goto done;
+		xml_flag_set(xf2, XML_FLAG_DEL);
 		continue;
 	    }
 	    /* These two shouldnt happen since revision is key, just ignore */
-	    if ((mrev = xml_find_body(xm, "revision")) == NULL)
+	    if ((frev = xml_find_body(xf, "revision")) == NULL)
 		continue;
 	    if ((srev = xml_find_body(xs, "revision")) == NULL)
 		continue;
-	    if (strcmp(mrev, srev)==0){
-		/* 3b) File module-state matches system */
-		//		fprintf(stderr, "%s: Module %s: file \"%s\" and system revisions match\n", __FUNCTION__, name, mrev);
-	    }
-	    else{
+	    if (strcmp(frev, srev)!=0){
 		/* 3c) File module-state does not match system */
-		//		fprintf(stderr, "%s: Module %s: file \"%s\" and system \"%s\" revisions do not match\n", __FUNCTION__, name, mrev, srev);
-		if ((xm2 = xml_dup(xm)) == NULL)
+		if ((xf2 = xml_dup(xf)) == NULL)
 		    goto done;
-		if (xml_addsub(msd->md_mod, xm2) < 0)
+		if (xml_addsub(msdiff->md_diff, xf2) < 0)
 		    goto done;
+		xml_flag_set(xf2, XML_FLAG_CHANGE);
+	    }
+	}
+	/* 4) For each module state s in the system (xmodsystem) */
+	xs = NULL;
+	while ((xs = xml_child_each(xmodsystem, xs, CX_ELMNT)) != NULL) {
+	    if (strcmp(xml_name(xs), "module"))
+		continue; /* ignore other tags, such as module-set-id */
+	    if ((name = xml_find_body(xs, "name")) == NULL)
+		continue;
+	    /* 4a) If there is no such module in the file -> add to list mark as ADD */	    
+	    if ((xf = xpath_first(xmodfile, NULL, "module[name=\"%s\"]", name)) == NULL){
+		if ((xs2 = xml_dup(xs)) == NULL) 	  /* Make a copy of this modstate */
+		    goto done;
+		if (xml_addsub(msdiff->md_diff, xs2) < 0)   /* Add it to modstatediff */
+		    goto done;
+		xml_flag_set(xs2, XML_FLAG_ADD);
+		continue;
 	    }
 	}
     }
@@ -305,8 +324,8 @@ text_read_modstate(clicon_handle       h,
      * in all cases, whether CLICON_XMLDB_MODSTATE is on or not.
      * Clixon systems with CLICON_XMLDB_MODSTATE disabled ignores it
      */
-    if (xmodst){ 	
-	if (xml_purge(xmodst) < 0)
+    if (xmodfile){ 	
+	if (xml_purge(xmodfile) < 0)
 	    goto done;
     }
     retval = 0;
@@ -319,14 +338,14 @@ text_read_modstate(clicon_handle       h,
  * @param[in]  db    Symbolic database name, eg "candidate", "running"
  * @param[in]  yspec Top-level yang spec
  * @param[out] xp    XML tree read from file
- * @param[out] msd    If set, return modules-state differences
+ * @param[out] msdiff    If set, return modules-state differences
  */
 int
 xmldb_readfile(clicon_handle      h,
 	       const char         *db,
 	       yang_stmt          *yspec,
 	       cxobj             **xp,
-	       modstate_diff_t    *msd)
+	       modstate_diff_t    *msdiff)
 {
     int    retval = -1;
     cxobj *x0 = NULL;
@@ -373,7 +392,7 @@ xmldb_readfile(clicon_handle      h,
     /* From Clixon 3.10,datastore files may contain module-state defining
      * which modules are used in the file. 
      */
-    if (text_read_modstate(h, yspec, x0, msd) < 0)
+    if (text_read_modstate(h, yspec, x0, msdiff) < 0)
 	goto done;
     if (xp){
 	*xp = x0;
@@ -399,7 +418,7 @@ xmldb_readfile(clicon_handle      h,
  * @param[in]  nsc    External XML namespace context, or NULL
  * @param[in]  xpath  String with XPATH syntax. or NULL for all
  * @param[out] xret   Single return XML tree. Free with xml_free()
- * @param[out] msd    If set, return modules-state differences
+ * @param[out] msdiff    If set, return modules-state differences
  * @retval     0      OK
  * @retval     -1     Error
  * @see xmldb_get  the generic API function
@@ -410,7 +429,7 @@ xmldb_get_nocache(clicon_handle       h,
 		  cvec               *nsc,
 		  char               *xpath,
 		  cxobj             **xtop,
-		  modstate_diff_t    *msd)
+		  modstate_diff_t    *msdiff)
 {
     int             retval = -1;
     char           *dbfile = NULL;
@@ -426,7 +445,7 @@ xmldb_get_nocache(clicon_handle       h,
 	clicon_err(OE_YANG, ENOENT, "No yang spec");
 	goto done;
     }
-    if (xmldb_readfile(h, db, yspec, &xt, msd) < 0)
+    if (xmldb_readfile(h, db, yspec, &xt, msdiff) < 0)
 	goto done;
     /* Here xt looks like: <config>...</config> */
     /* Given the xpath, return a vector of matches in xvec */
@@ -483,7 +502,7 @@ xmldb_get_nocache(clicon_handle       h,
  * @param[in]  nsc    External XML namespace context, or NULL
  * @param[in]  xpath  String with XPATH syntax. or NULL for all
  * @param[out] xret   Single return XML tree. Free with xml_free()
- * @param[out] msd    If set, return modules-state differences
+ * @param[out] msdiff    If set, return modules-state differences
  * @retval     0      OK
  * @retval     -1     Error
  * @see xmldb_get  the generic API function
@@ -494,7 +513,7 @@ xmldb_get_cache(clicon_handle    h,
 		cvec            *nsc,
 		char            *xpath,
 		cxobj          **xtop,
-		modstate_diff_t *msd)
+		modstate_diff_t *msdiff)
 {
     int             retval = -1;
     yang_stmt      *yspec;
@@ -514,7 +533,7 @@ xmldb_get_cache(clicon_handle    h,
     de = clicon_db_elmnt_get(h, db);
     if (de == NULL || de->de_xml == NULL){ /* Cache miss, read XML from file */
 	/* If there is no xml x0 tree (in cache), then read it from file */
-	if (xmldb_readfile(h, db, yspec, &x0t, msd) < 0)
+	if (xmldb_readfile(h, db, yspec, &x0t, msdiff) < 0)
 	    goto done;
 	/* XXX: should we validate file if read from disk? 
 	 * Argument against: we may want to have a semantically wrong file and wish
@@ -585,7 +604,7 @@ xmldb_get_cache(clicon_handle    h,
  * @param[in]  xpath  String with XPATH syntax. or NULL for all
  * @param[in]  config If set only configuration data, else also state
  * @param[out] xret   Single return XML tree. Free with xml_free()
- * @param[out] msd    If set, return modules-state differences
+ * @param[out] msdiff    If set, return modules-state differences
  * @retval     0      OK
  * @retval     -1     Error
  */
@@ -595,7 +614,7 @@ xmldb_get_zerocopy(clicon_handle    h,
 		   cvec            *nsc,
 		   char            *xpath,
 		   cxobj          **xtop,
-		   modstate_diff_t *msd)
+		   modstate_diff_t *msdiff)
 {
     int             retval = -1;
     yang_stmt      *yspec;
@@ -614,7 +633,7 @@ xmldb_get_zerocopy(clicon_handle    h,
     de = clicon_db_elmnt_get(h, db);
     if (de == NULL || de->de_xml == NULL){ /* Cache miss, read XML from file */
 	/* If there is no xml x0 tree (in cache), then read it from file */
-	if (xmldb_readfile(h, db, yspec, &x0t, msd) < 0)
+	if (xmldb_readfile(h, db, yspec, &x0t, msdiff) < 0)
 	    goto done;
 	/* XXX: should we validate file if read from disk? 
 	 * Argument against: we may want to have a semantically wrong file and wish
@@ -689,7 +708,7 @@ xmldb_get(clicon_handle    h,
  * @param[in]  xpath  String with XPATH syntax. or NULL for all
  * @param[in]  copy   Force copy. Overrides cache_zerocopy -> cache 
  * @param[out] xret   Single return XML tree. Free with xml_free()
- * @param[out] msd    If set, return modules-state differences (upgrade code)
+ * @param[out] msdiff    If set, return modules-state differences (upgrade code)
  * @retval     0      OK
  * @retval     -1     Error
  * @code
@@ -710,7 +729,7 @@ xmldb_get0(clicon_handle    h,
 	   char            *xpath,
 	   int              copy,
 	   cxobj          **xret,
-	   modstate_diff_t *msd)
+	   modstate_diff_t *msdiff)
 {
     int               retval = -1;
 
@@ -720,7 +739,7 @@ xmldb_get0(clicon_handle    h,
 	 * Add default values in copy
 	 * Copy deleted by xmldb_free
 	 */
-	retval = xmldb_get_nocache(h, db, nsc, xpath, xret, msd);
+	retval = xmldb_get_nocache(h, db, nsc, xpath, xret, msdiff);
 	break;
     case DATASTORE_CACHE_ZEROCOPY:
 	/* Get cache (file if empty) mark xpath match in original tree 
@@ -728,7 +747,7 @@ xmldb_get0(clicon_handle    h,
 	 * Default values and markings removed in xmldb_clear
 	 */
 	if (!copy){
-	    retval = xmldb_get_zerocopy(h, db, nsc, xpath, xret, msd);
+	    retval = xmldb_get_zerocopy(h, db, nsc, xpath, xret, msdiff);
 	    break;
 	}
 	/* fall through */
@@ -737,7 +756,7 @@ xmldb_get0(clicon_handle    h,
 	 * Add default values in copy, return copy
 	 * Copy deleted by xmldb_free
 	 */
-	retval = xmldb_get_cache(h, db, nsc, xpath, xret, msd);
+	retval = xmldb_get_cache(h, db, nsc, xpath, xret, msdiff);
 	break;
     }
     return retval;
diff --git a/lib/src/clixon_plugin.c b/lib/src/clixon_plugin.c
index f38383e4..d34e3195 100644
--- a/lib/src/clixon_plugin.c
+++ b/lib/src/clixon_plugin.c
@@ -793,9 +793,6 @@ typedef struct {
     const char       *uc_fnstr;     /* Stringified fn name for debug */
     void             *uc_arg;	    /* Application specific argument to cb */
     char             *uc_namespace; /* Module namespace */
-    uint32_t          uc_rev;       /* Module revision (to) in YYYYMMDD format or 0 */
-    uint32_t          uc_from;      /* Module revision (from) or 0 in YYYYMMDD format */
-
 } upgrade_callback_t;
 
 /* List of rpc callback entries XXX hang on handle */
@@ -808,8 +805,6 @@ static upgrade_callback_t *upgrade_cb_list = NULL;
  * @param[in]  fnstr     Stringified function for debug
  * @param[in]  arg       Domain-specific argument to send to callback 
  * @param[in]  namespace Module namespace (if NULL all modules) 
- * @param[in]  from      From module revision (0 from any revision)
- * @param[in]  revision  To module revision (0 means module obsoleted)
  * @retval     0         OK
  * @retval    -1         Error
  * @see upgrade_callback_call  which makes the actual callback
@@ -819,8 +814,6 @@ upgrade_callback_reg_fn(clicon_handle     h,
 			clicon_upgrade_cb cb,
 			const char       *fnstr,
 			char             *namespace,
-			uint32_t          from,
-			uint32_t          revision,
 			void             *arg)
 {
     upgrade_callback_t *uc;
@@ -835,8 +828,6 @@ upgrade_callback_reg_fn(clicon_handle     h,
     uc->uc_arg  = arg;
     if (namespace)
 	uc->uc_namespace  = strdup(namespace);
-    uc->uc_rev = revision;
-    uc->uc_from = from;
     ADDQ(uc, upgrade_cb_list);
     return 0;
  done:
@@ -864,14 +855,14 @@ upgrade_callback_delete_all(clicon_handle h)
     return 0;
 }
 
-/*! Search Upgrade callbacks and invoke if module match
+/*! Upgrade specific module identified by namespace, search matching callbacks
  *
  * @param[in]  h       clicon handle
  * @param[in]  xt      Top-level XML tree to be updated (includes other ns as well)
- * @param[in]  modname Name of module
- * @param[in]  modns   Namespace of module (for info)
- * @param[in]  from    From revision on the form YYYYMMDD
- * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
+ * @param[in]  ns      Namespace of module
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL or _CHANGE
+ * @param[in]  from    From revision on the form YYYYMMDD (if DEL or CHANGE)
+ * @param[in]  to      To revision on the form YYYYMMDD (if ADD or CHANGE)
  * @param[out] cbret   Return XML (as string in CLIgen buffer), on invalid
  * @retval -1  Error
  * @retval  0  Invalid - cbret contains reason as netconf
@@ -881,7 +872,8 @@ upgrade_callback_delete_all(clicon_handle h)
 int
 upgrade_callback_call(clicon_handle h,
 		      cxobj        *xt,
-		      char         *namespace,
+		      char         *ns,
+		      uint16_t      op,
 		      uint32_t      from,
 		      uint32_t      to,
 		      cbuf         *cbret)
@@ -903,23 +895,21 @@ upgrade_callback_call(clicon_handle h,
 	 *   - Registered from revision >= from AND
          *   - Registered to revision <= to (which includes case both 0)
 	 */
-	if (uc->uc_namespace == NULL || strcmp(uc->uc_namespace, namespace)==0)
-	    if ((uc->uc_from == 0) ||
-		(uc->uc_from >= from && uc->uc_rev <= to)){
-		if ((ret = uc->uc_callback(h, xt, namespace, from, to, uc->uc_arg, cbret)) < 0){
-		    clicon_debug(1, "%s Error in: %s", __FUNCTION__, uc->uc_namespace);
+	if (uc->uc_namespace == NULL || strcmp(uc->uc_namespace, ns)==0){
+	    if ((ret = uc->uc_callback(h, xt, ns, op, from, to, uc->uc_arg, cbret)) < 0){
+		clicon_debug(1, "%s Error in: %s", __FUNCTION__, uc->uc_namespace);
+		goto done;
+	    }
+	    if (ret == 0){
+		if (cbuf_len(cbret)==0){	
+		    clicon_err(OE_CFG, 0, "Validation fail %s(%s): cbret not set",
+			       uc->uc_fnstr, ns);
 		    goto done;
 		}
-		if (ret == 0){
-		    if (cbuf_len(cbret)==0){	
-			clicon_err(OE_CFG, 0, "Validation fail %s(%s): cbret not set",
-				   uc->uc_fnstr, namespace);
-			goto done;
-		    }
-		    goto fail;
-		}
-		nr++;
+		goto fail;
 	    }
+	    nr++;
+	}
 	uc = NEXTQ(upgrade_callback_t *, uc);
     } while (uc != upgrade_cb_list);
     retval = 1;
diff --git a/lib/src/clixon_xml_changelog.c b/lib/src/clixon_xml_changelog.c
index 2336cd87..02bef24e 100644
--- a/lib/src/clixon_xml_changelog.c
+++ b/lib/src/clixon_xml_changelog.c
@@ -356,6 +356,7 @@ changelog_iterate(clicon_handle h,
  * @param[in]  h       Clicon handle 
  * @param[in]  xt      Top-level XML tree to be updated (includes other ns as well)
  * @param[in]  namespace Namespace of module (for info)
+ * @param[in]  op      One of XML_FLAG_ADD, _DEL, _CHANGE
  * @param[in]  from    From revision on the form YYYYMMDD
  * @param[in]  to      To revision on the form YYYYMMDD (0 not in system)
  * @param[in]  arg     User argument given at rpc_callback_register() 
@@ -367,12 +368,13 @@ changelog_iterate(clicon_handle h,
  */
 int
 xml_changelog_upgrade(clicon_handle h,       
-		       cxobj        *xt,      
-		       char         *namespace,
-		       uint32_t      from,
-		       uint32_t      to,
-		       void         *arg,     
-		       cbuf         *cbret)
+		      cxobj        *xt,      
+		      char         *namespace,
+		      uint16_t      op,
+		      uint32_t      from,
+		      uint32_t      to,
+		      void         *arg,     
+		      cbuf         *cbret)
 {
     int        retval = -1;
     cxobj     *xchlog; /* changelog */
diff --git a/lib/src/clixon_yang_module.c b/lib/src/clixon_yang_module.c
index d3a8c030..38632e48 100644
--- a/lib/src/clixon_yang_module.c
+++ b/lib/src/clixon_yang_module.c
@@ -101,10 +101,8 @@ modstate_diff_free(modstate_diff_t *md)
 	return 0;
     if (md->md_set_id)
        free(md->md_set_id);
-    if (md->md_del)
-	xml_free(md->md_del);
-    if (md->md_mod)
-	xml_free(md->md_mod);
+    if (md->md_diff)
+	xml_free(md->md_diff);
     free(md);
     return 0;
 }
@@ -375,13 +373,13 @@ yang_modules_state_get(clicon_handle    h,
 
 /*! For single module state with namespace, get revisions and send upgrade callbacks
  * @param[in]  h        Clicon handle
- * @param[in]  xt      Top-level XML tree to be updated (includes other ns as well)
- * @param[in]  xs       XML module state (for one yang module)
+ * @param[in]  xt       Top-level XML tree to be updated (includes other ns as well)
+ * @param[in]  xd       XML module state diff (for one yang module)
  * @param[in]  xvec     Help vector where to store XML child nodes (??)
  * @param[in]  xlen     Length of xvec
  * @param[in]  ns0      Namespace of module state we are looking for
- * @param[in]  deleted  If set, dont look for system yang module and "to" rev
- * @param[out] cbret Netconf error message if invalid
+ * @param[in]  op       add,del, or mod
+ * @param[out] cbret    Netconf error message if invalid
  * @retval     1        OK
  * @retval     0        Validation failed (cbret set)
  * @retval    -1        Error
@@ -389,9 +387,8 @@ yang_modules_state_get(clicon_handle    h,
 static int
 mod_ns_upgrade(clicon_handle h,
 	       cxobj        *xt,
-	       cxobj        *xs,
+	       cxobj        *xmod,
 	       char         *ns,
-	       int           deleted,
 	       cbuf         *cbret)
 {
     int        retval = -1;
@@ -403,15 +400,14 @@ mod_ns_upgrade(clicon_handle h,
     int        ret;
     yang_stmt *yspec;
 
-    /* Make upgrade callback for this XML, specifying the module 
-     * namespace, from and to revision.
-     */
-    if ((b = xml_find_body(xs, "revision")) != NULL) /* Module revision */
-	if (ys_parse_date_arg(b, &from) < 0)
-	    goto done;
-    if (deleted)
-	to = 0;
-    else {	    /* Look up system module (alt send it via argument) */
+    /* If modified or removed get from revision from file */
+    if (xml_flag(xmod, (XML_FLAG_CHANGE|XML_FLAG_DEL)) != 0x0){
+	if ((b = xml_find_body(xmod, "revision")) != NULL) /* Module revision */
+	    if (ys_parse_date_arg(b, &from) < 0)
+		goto done;
+    }
+    /* If modified or added get to revision from system */
+    if (xml_flag(xmod, (XML_FLAG_CHANGE|XML_FLAG_ADD)) != 0x0){
 	yspec = clicon_dbspec_yang(h);
 	if ((ymod = yang_find_module_by_namespace(yspec, ns)) == NULL)
 	    goto fail;
@@ -420,7 +416,9 @@ mod_ns_upgrade(clicon_handle h,
 	if (ys_parse_date_arg(yang_argument_get(yrev), &to) < 0)
 	    goto done;
     }
-    if ((ret = upgrade_callback_call(h, xt, ns, from, to, cbret)) < 0)
+    if ((ret = upgrade_callback_call(h, xt, ns,
+				     xml_flag(xmod, (XML_FLAG_CHANGE|XML_FLAG_ADD|XML_FLAG_CHANGE)),
+				     from, to, cbret)) < 0)
 	goto done;
     if (ret == 0) /* XXX ignore and continue? */
 	goto fail;
@@ -447,33 +445,25 @@ clixon_module_upgrade(clicon_handle    h,
 		      modstate_diff_t *msd,
    		      cbuf            *cbret)
 {
-    int        retval = -1;
-    char      *ns;           /* Namespace */
-    cxobj     *xs;            /* XML module state */
-    int        ret;
+    int      retval = -1;
+    char   *ns;           /* Namespace */
+    cxobj  *xmod;           /* XML module state diff */
+    int     ret;
 
-    if (msd == NULL)
+    if (msd == NULL){
+	clicon_err(OE_CFG, EINVAL, "No modstate");
+	goto done;
+    }
+    if (msd->md_status == 0) /* No modstate in startup */
 	goto ok;
     /* Iterate through xml modified module state */
-    xs = NULL;
-    while ((xs = xml_child_each(msd->md_mod, xs, CX_ELMNT)) != NULL) {
+    xmod = NULL;
+    while ((xmod = xml_child_each(msd->md_diff, xmod, CX_ELMNT)) != NULL) {
 	/* Extract namespace */
-	if ((ns = xml_find_body(xs, "namespace")) == NULL)
+	if ((ns = xml_find_body(xmod, "namespace")) == NULL)
 	    goto done;
 	/* Extract revisions and make callbacks */
-	if ((ret = mod_ns_upgrade(h, xt, xs, ns, 0, cbret)) < 0)
-	    goto done;
-	if (ret == 0)
-	    goto fail;
-    }
-    /* Iterate through xml deleted module state */
-    xs = NULL;
-    while ((xs = xml_child_each(msd->md_del, xs, CX_ELMNT)) != NULL) {
-	/* Extract namespace */
-	if ((ns = xml_find_body(xs, "namespace")) == NULL)
-	    continue;
-	/* Extract revisions and make callbacks (now w deleted=1)  */
-	if ((ret = mod_ns_upgrade(h, xt, xs, ns, 1, cbret)) < 0)
+	if ((ret = mod_ns_upgrade(h, xt, xmod, ns, cbret)) < 0)
 	    goto done;
 	if (ret == 0)
 	    goto fail;