"This Opus 1.3.1 minor release fixes an issue with the analysis on files with digital silence (all zeros), especially on x87 builds (mostly affects 32-bit builds). It also includes two new features:
A new OPUS_GET_IN_DTX query to know if the encoder is in DTX mode (last frame was either a comfort noise frame or not encoded at all)
A new (and still experimental) CMake-based build system that is eventually meant to replace the VS2015 build system (the autotools one will stay)."http://opus-codec.org/release/stable/2019/04/12/libopus-1_3_1.html
You can replace your existing opusenc.exe in MusicBee/Codec with the one inside this package if the new revision is of interest to you.