It definitely should include file transfers, according to their blog post: https://blog.whatsapp.com/10000618/end-to-end-encryption https://blog.whatsapp.com/10

It definitely should include file transfers, according to their blog post: https://blog.whatsapp.com/10000618/end-to-end-encryption https://blog.whatsapp.com/10000618/end-to-end-encryption. Are you sure encryption was active, both devices on the latest version? Is there a chance that the conversion was done on either of the devices? Otherwise, yeah, something isn't right.