Late yesterday, I released v1.2 of Opus GUI:
This new release brings several improvements. v1.1 was also released but was immediately superseded by v1.2 due to an uncorrected bitrate bug.
First, the GUI will now display the opusenc.exe version being used. This is useful because sometimes, new opusenc versions are released which I personally compile and try to see if there's new improvements to the audio files.