The recent change completely removed support for general URIs and enforced strict URL validation which was breaking backwards compatibility and was not user friendly at all.
This patch finally adds full URI support with basic validation and fixes some older xhtml strict issues.
Please note we do not try to explain the difference between URL and URI to our users. Also keep in mind that mod/url has XSS risk and does not do any security validation of the data.
Petr Skoda