After reading about the new Arabic URLs, and with more languages to come, how should URL validation be done for internationalized applications? Does the validation change at all and will existing solutions break? Is regex still a good approach? If so, what would that regex look like? If not, what's a good strategy? What are some good resources to read more on the topic?

I ask this because it has the potential to cause a good many localized applications to have to be rewritten if they have to validate URLs at any point.