Hi foxie
All legacy claimants will have to apply for UC when they receive a Notice letter from the DWP asking them to do so.
As a word of warning, there may be a number of scam emails floating about by trying to rip people off, it happened during covid-19 so just be wary when responding to any emails you recieve on line.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems