Hi,
Currently the matrix-appservice-irc service defaults to version 1.0.1, but upstream is at version 3.0.5, which was released less than a month ago:
https://github.com/matrix-org/matrix-appservice-irc/releases
I haven't personally tested to see if there are any breaking changes with the latest version, but given that there are a number of security fixes in the from 1.0.1 to 3.0.5, I believe it's a good idea to bump it.
Thanks.