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.

String path = null;
        Map<String, String> parameters = null;
        int i = url.indexOf('?'); 
        if (i >= 0) {
            String[] parts = url.substring(i + 1).split("&");
            parameters = new HashMap<>();
            for (String part : parts) {
                part = part.trim();
                if (part.length() > 0) {
                    int j = part.indexOf('=');
                    if (j >= 0) {
                        parameters.put(part.substring(0, j), part.substring(j + 1));
                    } else {
                        parameters.put(part, part);
                    }
                }
            }
            url = url.substring(0, i);
        }
        i = url.indexOf("://");
        if (i >= 0) {
            if (i == 0) {
                throw new IllegalStateException("url missing protocol: \"" + url + "\"");
            }
            protocol = url.substring(0, i);
            url = url.substring(i + 3);
        } else {
            
            i = url.indexOf(":/");
            if (i >= 0) {