I don't think you would notice any difference from the 8th gen to 13th gen. I think that the only differences were software changes to support some additional phones. Since your iPhone works, nothing else would likely change. (I have a 12th gen, and I can not adjust the volume with a iPhone 3GS.)

When you say "limited features," what is missing? The only thing really missing is that you can not do voice dialing without first recording voice tags. Other than that, it is probably the most feature-rich BT system you can get in any car at any price.

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input