If this is in relation to Salisbury, and the contribution of the RHTT not running, you can almost be certain that there will be a recommendation that drivers are made aware of this so that they can drive to the anticipated conditions.
I was sure this was communicated to drivers already, but I'm probably wrong in that regard.
Most communication goes on between control and drivers book on points, if it isn't something that results in the need for an immediate caution (which would be applied by the signaller). There is evidently a gap there where urgent but not necessarily emergency or immediate info needs to be communicated. Never been keen on tablets or phones due to their potentially distracting nature for drivers. I know that they likely wouldn't be accepted at ScotRail for example.
There was many a situation at ScotRail where messages would be passed on via station staff from control, and drivers would completely disregard them.