--- dict-sql-private.h.orig	2019-05-19 19:00:12.395887496 +0200
+++ dict-sql-private.h	2019-05-19 19:04:00.147601310 +0200
@@ -13,6 +13,7 @@
 	HASH_TABLE(const char *, struct sql_prepared_statement *) prep_stmt_hash;
 
 	bool has_on_duplicate_key:1;
+	bool has_on_conflict_do_update:1;
 };
 
 #endif
--- dict-sql.c.orig	2019-05-19 18:58:02.435194691 +0200
+++ dict-sql.c	2019-05-19 19:17:52.613253822 +0200
@@ -105,8 +105,10 @@
 	i_zero(&sql_set);
 	sql_set.driver = driver->name;
 	sql_set.connect_string = dict->set->connect;
-	/* currently pgsql and sqlite don't support "ON DUPLICATE KEY" */
+	/* pgsql and sqlite don't support "ON DUPLICATE KEY" */
+	/* mysql and sqlite don't support "ON CONFLICT DO UPDATE" */
 	dict->has_on_duplicate_key = strcmp(driver->name, "mysql") == 0;
+	dict->has_on_conflict_do_update = strcmp(driver->name, "pgsql") == 0;
 
 	if (sql_db_cache_new(dict_sql_db_cache, &sql_set, &dict->db, error_r) < 0) {
 		pool_unref(&pool);
@@ -1108,12 +1110,15 @@
 
 	str_append_str(prefix, suffix);
 	str_append_c(prefix, ')');
-	if (!dict->has_on_duplicate_key) {
+	if (dict->has_on_duplicate_key ) {
+		str_append(prefix, " ON DUPLICATE KEY UPDATE ");
+	} else if(dict->has_on_conflict_do_update)  {
+		str_append(prefix, " ON CONFLICT DO UPDATE SET ");
+	} else {
 		*stmt_r = sql_dict_transaction_stmt_init(ctx, str_c(prefix), &params);
 		return 0;
 	}
 
-	str_append(prefix, " ON DUPLICATE KEY UPDATE ");
 	for (i = 0; i < field_count; i++) {
 		const char *first_value_field =
 			t_strcut(fields[i].map->value_field, ',');