My 2.4G stopped working after the update, I eventually got it working by disabling 2.4G Wireless, enabling it again and then changing the channel it was using. That seemed to resolve it. 5G was not affected by the change!.
On the Ask the Expert Live Chat on the HH 4 there was this statement
What about it moderators ?
I just noticed my hub updated overnight, and the profile dropped from 39Mbps to 36Mbps not much but a drop!
Hopefully the DLM system will bring your profiles back up after a couple of weeks, as advised on this forum?
Didn't have to did a power recycle on open reach modem and HH4 and profile went back up - and yes I know plenty on here advise against this although in bt's own 'help' pages they advise that power recycling 'Can often solve speed and connection problems with your fibre broadband service'