regarding open source downloads, please read here below:
Open Source Downloads
oifii 1997: https://oifii.org/oifii/
oifii 2012: https://oifii.org/ns-org/nsd/ar/cp/audio_spi/lib-src/oifii/
oifii 2013: https://oifii.org/ns-org/nsd/ar/cp/audio_spi/lib-src/
oifii 2017: https://oifii.audiospi.com/files.html
oifii 2020: source code, cloud account ownerships sold by SPI