Since I haven’t seen it mentioned anywhere on the forum, I can confirm that Fairphone 4 supports aptX Adaptive as well.
When reading through various threads on the forum there seems to be some confusion about what codecs the Fairphone 4 actually supports. Below is a list of Bluetooth Audio Codecs and other Audio Output formats I’ve been able to personally confirm in case anyone seeks this information in the future:
List of audio codecs confirmed working and with which devices. All tests performed on Fairphone 4 software build FP4.FP3T.A.107.20220316::
- SBC: Bang&Olufsen Beoplay Portal PC/PS, Sennheiser Momentum True Wireless 2, Fairphone True Wireless Stereo Earbuds
- AAC: Bang&Olufsen Beoplay Portal PC/PS, Sennheiser Momentum True Wireless 2, Fairphone True Wireless Stereo Earbuds
- aptX audio: Bang&Olufsen Beoplay Portal PC/PS, Sennheiser Momentum True Wireless 2
- aptX HD audio: Bang&Olufsen Beoplay Portal PC/PS
- aptX Adaptive audio: Bang&Olufsen Beoplay Portal PC/PS
I don’t have any aptX LL (Low Latency) audio or Sony LDAC bluetooth devices to test with so I am unable to confirm or deny support for these personally. Sony LDAC appears supported as per other users in this thread:
I can also confirm that the Fairphone 4 supports USB-C native headphones like the Bang&Olufsen Beoplay Portal PC/PS, and they show up as USB-C Headphones on the phone.
Hopefully someone finds this list useful in the future.