Daniel-Constantin Mierla writes:
the question is which format is the correct one (entity value with uri
shcema (sip:) or without)? Or maybe both formats are ok?!?
as it was mentioned by the author, all examples in standards include uri
scheme and in the document syntax specify uri. uri always contains uri
scheme, otherwise it is not uri.
It was not clear from your previous statement that your experience
with other cases when there was no schema was the right or wrong
way. Because the patch adds schema to entity in an xml doc
constructed by presence_dialoginfo module. Therefore seems to be a
bug in the module if sip: is missing, which is fixed by that patch.