At this moment fails on ARM Cortex-A53 and Cortex-A55, works on RISC-V 64.
wget https://downloads.xiph.org/releases/opus/opus-1.5.1.tar.gz
tar -xf opus-1.5.1.tar.gz
cd opus-1.5.1
sudo apt install autoconf automake libtool gcc make
./configure
sudo make install
This version brings non-marginal improvements for spoken content at low bitrate.