After installing Directory Opus 13.15 on my laptop, I see some of the text having placeholders instead of showing the correct text. Not every text does that. Most prominently, it's on the text on the bar here (notice the {η!} {η!}):
At the moment, I can see it on the Greek translation. It's pretty possible that the placeholder text was also translated, causing issues like this.
We'll check the Greek translation, but you can also fix this right now by going to Preferences / File Displays / Status Bar and changing any {η!} to {h!}.
Thanks! That has been fixed for the next update. (After the update, you may need to reset the File Type Group, or its InfoTip, for the change to take effect.)