Starting with Smack version 4.1.0 the message delivery receipt package contains the type attribute, e.g. type=‘chat’.
This is a change and makes new clients incompatible to older clients. We observe also problems with clients of other platforms which do not send the type attribute.
According to XEP-0184 specification this attribute is not included:
<message firstname.lastname@example.org/throne' id='bi29sg183b4v' email@example.com/westminster'> <received xmlns='urn:xmpp:receipts' id='richard2-4.1.247'/> </message>
Please remove the type attribute as it was before.