Why is the newest model AS90TA only BT version 4.2, but older model AS90T and AS90P is 5.0?

All of the Aria Pro, Aria Podio and the Aria Me have Bluetooth 5.0 compatible hardware. The Aria Me however, has a personal hearing profile customization feature. The embedded software and associated app for this feature are both certified for Bluetooth 4.2 - hence the registration of this model under v4.2. From a connectivity and audio quality point of view there is no difference between these two models.

Please feel free to contact us at support@avantree.com for more questions if you have.