Holiday for Slovakia (sk_sk) has wrong date for Teachers day. It should be 28.March, not 28.April.
This is a pretty simple fix. Here is the exact line of code that is wrong: https://cgit.kde.org/kholidays.git/tree/holidays/plan2/holiday_sk_sk#n55 Would you like to try your hand at submitting a patch? I am willing to help you, and we have excellent documentation: - https://community.kde.org/Get_Involved/development - https://community.kde.org/Infrastructure/Phabricator
Git commit 9c8aa21205db76d9677855e760ee155bf35cc325 by Allen Winter. Committed on 28/04/2018 at 13:39. Pushed by winterz into branch 'master'. holidays/plan2/holiday_sk_sk - Teacher's Day fix FIXED-IN: 5.46 M +1 -1 holidays/plan2/holiday_sk_sk https://commits.kde.org/kholidays/9c8aa21205db76d9677855e760ee155bf35cc325