Yes, I’ve looked into the issue in more details after I wrote my previous message. I’ve just released v21.3.906, where I added the Uppercase (Locale-dependent), Lowercase (Locale-dependent), and Capitalize (Locale-dependent) commands. Please make sure “Turkish” is selected in the Sort page of the Customize dialog box, and use one of these locale-dependent casing commands. They will convert İ <=> i, and I <=> ı correctly. Please try this new latest beta version, and let me know if there are any other issues with Turkish alphabet. Thank you.