Hello all! I have a working solution for my 2017 macbook pro which only has usb C inputs.
Picked this up from target last night, last one in the store. Confirmed today that im using my sonic port vx on a macbook pro 2017 running the most current os (catalina at time of this comment). I was able to plug right in, garageband recognized the interface, started playing right away.
Setup is as follows, both plugged into the macbook:
1. line 6 proprietary cable into the Anker lightning to usb C adapter
2. Micro SB to USB C converter for the power cable
https://www.target.com/p/anker-1-34-powerline-usb-c-to-lightning-audio-adapter-white/-/A-76625624?ref=tgt_adv_XS000000&AFID=google_pla_df&fndsrc=tgtao&CPNG=PLA_Electronics%2BShopping_Local&adgroup=SC_Electronics&LID=700000001170770pgs&network=g&device=c&location=9032443&ds_rl=1246978&ds_rl=1248099&gclid=EAIaIQobChMI0tDj36fz6AIVhsVkCh3HDAb8EAQYAiABEgKQ7_D_BwE&gclsrc=aw.ds