Translation:I found out that I have friends in Ukraine.
Some people argue that saying "I found out that, I have friends in Ukraine" is ungrammatical according to the sequence of tenses rules. Other people say, if one still has friends in Ukraine at present and wants to emphasize this fact, then it is an exception to the rules and "found ... have" can be used.
Both variants ("had" and "have") are accepted now.
Great you understood my question :) Thanks for solving this. I'm aware that tenses usually do not change mid-sentence in English, but this does seem (to me sound) like an appropriate case for that.
Is "Вкраїні" acceptable is spoken language? I've read it in songs and poetry so I'm not sure.
Not really, not in spoken or written. They use it in poetry and song lyrics sometimes (really rare) when the rhythm gets broken otherwise.