Clarification on RELP spec with regard to reply ordering

[croepha]

in reference to: https://github.com/rsyslog/librelp/blob/master/doc/relp.html

I may be reading it incorrectly, but it seems like the first couple of sentences are in conflict with each-other.

The server may reply in any order

Responses must be sent by the server in the exact same order as commands where received

I'm a bit confused by what this means practically...

Can syslog commands from the client be responded to out of order?, or is the next rsp command always going to be the lowest transaction for which there has not been an rsp seen?