Comment by Ballas

Not necessarily relevant to the C3, but I have seen others claim the same for S3, only for me to discover the variant they had was the one that requires the external antenna. For official Espressiv modules, the only difference is the position of an 0201 (maybe 0402) resistor, so they physically look identical depending on how good your eyesight is and if you know what to look for. (The part number also differs - but reading that all the way is like reading the manual - most people don't.)