On Thursday, 19 May 2022 at 22:14:31 UTC, kdevel wrote: > Free of charge I compiled and ran this for you: > > $ dmd lcb > $ ./lcb > input : A Ä > bright : a Ä > toLower (std.utf): a ä > input : A Ä > bright : a ä > toLower (std.utf): a ä > > See the problem? > You could have use "Ali Çehreli" as a test case :)