There are adhesive posters on the bridge, on the platforms, by the gates and leaflets with more details. Big orange ones, saying 'do not travel' although there are some newer ones which show where the rail replacement buses run (same as last August).
Only key difference is this time the buses are hourly, not half hourly, presumably as there were predictions of higher passenger numbers on a hot August weekend than late January.
The buses will run from Hitchin to Potters Bar (and back) via the basement of the Howard Centre. Buses will shuttle from Hatfield to St Albans, but as I said earlier, you'll be a LOT better off going to St Albans in the first place IMO. It's what I'll be doing.