F older letters size&sorting

[den500]

I hawe Roundcube Webmail 1.4.11. I have a problem sorting folders.
My users created folders in INBOX: folder1; fOlder2,  Folder3. But the roundcube displays - Folder3, fOlder2, folder1. how to make the size of letters in the name of the folders be ignored?
PS: My old Roundcube Webmail 1.3.8 - no this problem.

[den500]

Found a solution - need to change /etc/default/locale "C.UTF-8"change to "ru_UA.UTF-8"