MicroMPX+ adds support for bitrates between 176 kbit/s and 320 kbit/s.

Both sides need to support MicroMPX+ for this to work.

Please be aware that, especially at the lowest bitrates, certain benefits of MicroMPX might not be fully available. MicroMPX was made specifically for FM, which means that if it cannot encode at full quality, it adds artifacts that sound like FM reception artifacts, instead of way more annoying MP3/AAC-like artifacts. At low bitrates, this can become audible. MicroMPX+ includes information about those codec artifacts so the decoder can filter them out. That works very well, but the filtering can slightly change the waveform (*, moreso if the bitrate is lower), due to which we cannot guarrantee that a fully ITU-R.1268 (AKA "Stokkemask") compliant signal will still be compliant on the other end. Most audio processors don't even offer this feature, but for example Stereo Tool and the Omnia.9 do. While even a 176 kbit/s encoded Stereo Tool signal with ITU-R.1268 enabled will still be much closer to ITU-R.1268 than a signal without this. As far as we are aware, compliance to this standard is only mandatory in the Netherlands and Belgium.

GPS synchronization with better than 1 microsecond precision, intended for Single Frequency Networks.

The encoder must support GPS synchronisation as well, and you also need a GPS license for that encoder. Tthe MicroMPX software encoder and MicroMPX encoder in Stereo Tool support GPS synchronization.