diff --git a/kadmin/kadmin-commands.in b/kadmin/kadmin-commands.in
index 8fc300825..89e67610d 100644
--- a/kadmin/kadmin-commands.in
+++ b/kadmin/kadmin-commands.in
@@ -176,15 +176,17 @@ command = {
 	}
 	option = {
 		long = "hist-kvno-diff-clnt"
-		type = "string"
+		type = "integer"
 		argument = "kvno diff"
 		help = "historic keys allowed for client"
+		default = "-1"
 	}
 	option = {
 		long = "hist-kvno-diff-svc"
-		type = "string"
+		type = "integer"
 		argument = "kvno diff"
 		help = "historic keys allowed for service"
+		default = "-1"
 	}
 	option = {
 		long = "use-defaults"
@@ -379,15 +381,17 @@ command = {
 	}
 	option = {
 		long = "hist-kvno-diff-clnt"
-		type = "string"
+		type = "integer"
 		argument = "kvno diff"
 		help = "historic keys allowed for client"
+		default = "-1"
 	}
 	option = {
 		long = "hist-kvno-diff-svc"
-		type = "string"
+		type = "integer"
 		argument = "kvno diff"
 		help = "historic keys allowed for service"
+		default = "-1"
 	}
 	argument = "principal"
 	min_args = "1"
diff --git a/kadmin/mod.c b/kadmin/mod.c
index 017e4ac84..615105f9d 100644
--- a/kadmin/mod.c
+++ b/kadmin/mod.c
@@ -41,7 +41,7 @@ add_tl(kadm5_principal_ent_rec *princ, int type, krb5_data *data)
 
     tl = ecalloc(1, sizeof(*tl));
     tl->tl_data_next = NULL;
-    tl->tl_data_type = KRB5_TL_EXTENSION;
+    tl->tl_data_type = type;
     tl->tl_data_length = data->length;
     tl->tl_data_contents = data->data;
 
@@ -99,7 +99,7 @@ add_constrained_delegation(krb5_context contextp,
     if (buf.length != size)
 	abort();
 
-    add_tl(princ, KRB5_TL_EXTENSION, &buf);
+    add_tl(princ, KRB5_TL_EXTENSION, &buf); /* XXX wrong type */
 }
 
 static void
@@ -142,7 +142,7 @@ add_aliases(krb5_context contextp, kadm5_principal_ent_rec *princ,
     if (buf.length != size)
 	abort();
 
-    add_tl(princ, KRB5_TL_EXTENSION, &buf);
+    add_tl(princ, KRB5_TL_ALIASES, &buf);
 }
 
 static void
@@ -182,7 +182,41 @@ add_pkinit_acl(krb5_context contextp, kadm5_principal_ent_rec *princ,
     if (buf.length != size)
 	abort();
 
-    add_tl(princ, KRB5_TL_EXTENSION, &buf);
+    add_tl(princ, KRB5_TL_PKINIT_ACL, &buf);
+}
+
+static void
+add_kvno_diff(krb5_context context, kadm5_principal_ent_rec *princ,
+	      int is_svc_diff, krb5_kvno kvno_diff)
+{
+    krb5_error_code ret;
+    HDB_extension ext;
+    krb5_data buf;
+    size_t size = 0;
+    int type;
+
+    if (kvno_diff < 0)
+	return;
+    if (kvno_diff > 2048)
+	kvno_diff = 2048;
+
+    if (is_svc_diff) {
+	ext.data.element = choice_HDB_extension_data_hist_kvno_diff_svc;
+	ext.data.u.hist_kvno_diff_svc = (unsigned int)kvno_diff;
+	type = KRB5_TL_HIST_KVNO_DIFF_SVC;
+    } else {
+	ext.data.element = choice_HDB_extension_data_hist_kvno_diff_clnt;
+	ext.data.u.hist_kvno_diff_clnt = (unsigned int)kvno_diff;
+	type = KRB5_TL_HIST_KVNO_DIFF_CLNT;
+    }
+    ASN1_MALLOC_ENCODE(HDB_extension, buf.data, buf.length,
+		       &ext, &size, ret);
+    if (ret)
+	abort();
+    if (buf.length != size)
+	abort();
+
+    add_tl(princ, type, &buf);
 }
 
 static int
@@ -211,7 +245,9 @@ do_mod_entry(krb5_principal principal, void *data)
        e->kvno_integer != -1 ||
        e->constrained_delegation_strings.num_strings ||
        e->alias_strings.num_strings ||
-       e->pkinit_acl_strings.num_strings) {
+       e->pkinit_acl_strings.num_strings ||
+       e->hist_kvno_diff_clnt_integer != -1 ||
+       e->hist_kvno_diff_svc_integer != -1) {
 	ret = set_entry(context, &princ, &mask,
 			e->max_ticket_life_string,
 			e->max_renewable_life_string,
@@ -236,7 +272,14 @@ do_mod_entry(krb5_principal principal, void *data)
 	    add_pkinit_acl(context, &princ, &e->pkinit_acl_strings);
 	    mask |= KADM5_TL_DATA;
 	}
-
+	if (e->hist_kvno_diff_clnt_integer != -1) {
+	    add_kvno_diff(context, &princ, 0, e->hist_kvno_diff_clnt_integer);
+	    mask |= KADM5_TL_DATA;
+	}
+	if (e->hist_kvno_diff_svc_integer != -1) {
+	    add_kvno_diff(context, &princ, 1, e->hist_kvno_diff_clnt_integer);
+	    mask |= KADM5_TL_DATA;
+	}
     } else
 	ret = edit_entry(&princ, &mask, NULL, 0);
     if(ret == 0) {