So it says, and has said for a couple of days now... of course this is not unexpected - Chesstalk message forum has been sold and this maintenance is likely the transfer to the the new owners.
I am sure they have no real good estimate on when it will be complete, it will be interesting to see the new version when they are done - I understand the new owner will use a more up to date version of the forum software (Vbulletin) - that should eliminate many or all of the persistent bugs and exploits that haunted the old CT. Perhaps all the old forum posts will appear in an archive or maybe they will just carry on with no specific changes to the forums for now? We will see!