Serbian dinar is the currency in Kosovo
But still, they say euro is official currency since Kosovo's independency, so Kosovo hasn't had any currency before euro.
And, Kosovo "became a country" in 2008, so, there was no official currency in the Republic of Kosovo before Euro, right?
Either way, they're all "legal" tender. https://en.wikipedia.org/wiki/International_status_and_usage_of_the_euro#Zimbabwe
The Euro is one of the most boring currencies ever devised!
And what's really bizarre is how small they made the Euro. So small that the single-cent and two-cent coins were effectively obsolete before they were introduced. If they had made the Euro worth ten times what it is, then there would have been a good many years' worth of inflation built in. Or even been really far-sighted and made it worth 100 times as much, and divided it into mils. But that would have required some imagination...