Leave it to Forgeworld to be already getting hard at work for their FAQs before the ink dries. The new Space Marines have several books that need to be updated, especially along the lines of the Dreadnoughts getting updated. Here is a readers question and answers from Forgeworld.
via a reader on Faeit 212
I have a contemptor mortis dreadnought and a chaplain dreadnought. I was
curious if the rules for these will be FAQed or updated to be brought in
line with dreadnoughts in the new space marines codex, which now have more
attacks and chapter tactics?
Thanks for your e-mail. Our rules team are currently working on several
FAQs and errata to update our older publications and these will be released
in the near future. We will, of course, pass your questions on to them.
In the meantime we think it's fair to use any MK4 or MK5 Dreadnoughts with
the amount of attacks that they now have in the new Codex: Space Marines
but Any Contemptors would still have the amount of attacks that are printed
in their current rules.
If there is anything further we can do to assist you, or if you have any
queries about the information we have requested or provided, please