I can’t find any mention on the internets from the Seeed folks providing a direct response to this question.
Closest I’ve found goes something like, “all Xadow expansion modules will be migrated to the 11 pin connector” (i.e. “V2” Xadow modules). The Xadow docs on the Seeed wiki still reference only the 12 pin line. That’s right, there’s not a single reference to 11 pin Xadow connectors in the Xadow category of the Seeed wiki. You have to go to the RePhone section (or the store) to find any info on the surprise obfuscation of all prior Xadow modules sold.
Despite packing capable tech in a diminutive footprint, the Xadow line hasn’t managed to gain traction. My guess is Seeed is using the hype behind RePhone as an opportunity to reintroduce Xadow, this time with “V2” connectors.
Seeed is banking on selling enough new Xadow modules that adoption numbers will justify their decision not to design a migration route for the few early adopters.
Unfortunately, they can’t make the above justification until it pans out. So instead of addressing questions about V1/V2 compatibility directly (if at all), Seeed’s response has been, “Yes, someday in the future, all Xadow modules will be available in an 11 pin ‘V2’ version. Have you seen the RePhone? It’s great! And it supports new 11 pin Xadow modules that we haven’t made yet!” Which doesn’t actually answer the question.
Here are a few questions Seeed can answer to help early Xadow adopters decide what to do next:
“Can I use 12 pin main/modules with 11 pin main/modules?”
“Will you be making adapters?”
“If not, what modifications are necessary {to module X} to make them compatible?”
“How do the two busses compare (eg. ‘Int’ vs ‘Data’ pins)?”
“Is Xadow 12 pin now obsolete?”
“When will you be updating the Wiki to mention the obsolescence of 12 pin modules?”
“When will you be updating the Xadow section in the Wiki to mention the existence of 11 pin Xadow modules?”