The 6.17.x line was returning 406 not-acceptable from WhatsApp's pre-key
endpoint when distributing sender keys to per-device JIDs (e.g.
40471728529510:18@s.whatsapp.net). This blocked every group send
regardless of group size.
Baileys 7.0.0-rc series tracks WhatsApp's current protocol. API is
drop-in compatible — typecheck clean, no source changes needed.
Re-pair required: 6.x signal session files are not portable to 7.x.
yiekheng
83d9bf6e9b