lower version, for example 2.6.8
```properties
dubbo.provider.version=1.0
```

2.7.6 failed to recognize the provider url with 'default.version=1.0' key,  it only takes 'version.1.0' into consideration.

@Test
    public void testParseUrl2() {
        String address = "192.168.0.1";
        String backupAddress1 = "192.168.0.2";
        String backupAddress2 = "192.168.0.3";
        Map<String, String> parameters = new HashMap<String, String>();
        parameters.put("username", "root");
        parameters.put("password", "alibaba");
        parameters.put("port", "10000");
        parameters.put("protocol", "dubbo");
        URL url = UrlUtils.parseURL(address + "," + backupAddress1 + "," + backupAddress2, parameters);
        assertEquals("192.168.0.1:10000", url.getAddress());
        assertEquals("root", url.getUsername());
        assertEquals("alibaba", url.getPassword());
        assertEquals(10000, url.getPort());
        assertEquals("dubbo", url.getProtocol());
        assertEquals("192.168.0.2" + "," + "192.168.0.3", url.getParameter("backup"));
    }
    @Test
    public void testParseUrls() {
        String addresses = "192.168.0.1|192.168.0.2|192.168.0.3";
        Map<String, String> parameters = new HashMap<String, String>();
        parameters.put("username", "root");
        parameters.put("password", "alibaba");
        parameters.put("port", "10000");
        parameters.put("protocol", "dubbo");
        List<URL> urls = UrlUtils.parseURLs(addresses, parameters);
        assertEquals("192.168.0.1" + ":10000", urls.get(0).getAddress());
        assertEquals("192.168.0.2" + ":10000", urls.get(1).getAddress());
    }