What is the bit rate limit for AAC music while using Bluetooth headphone?

I'm using the Beyerdynamic Byron BTA as an alternative to the original Earpods.

But I'm confused about the Bluetooth AAC codec.

BTA supports both APTX and AAC codec, but neither Beyerdynamic nor Apple has listed the bit rate requirement of the AAC file.

So when importing songs from CDs, I need to know the bit rate limit. 256kbps or 320kbps?

I googled for several days and only found this document from Apple. In page 16, there's a table listed:

But this document was published in 2013, and I assume that it is outdated as of now?

I called Apple Support but nobody seems to know the answer. They suggested me to contact Apple developer support. I think that since AAC codec is kind of a protocol and there must be a detailed document like an RFC. Does any one know where I can find it?

As SBC codec supports 345 kbps for stereo streams, I suppose it's not a technology problem IF Apple want to support 320kbps AAC stream over Bluetooth, right?

Thanks for any useful information!