Old felt soles can be replaced, and new soles attached, with a little prep work and Aquaseal adhesive.
To attach New felt soles, remove old felt (if necessary). Lightly roughen rubber soles with sandpaper then wipe rubber soles with Cotol-240 or isopropyl alcohol.
Attach Felt Sole to Boot
Apply Aquaseal to outer edge of new felt soles and attach to boot. Clamp in place and allow Aquaseal to dry level 8 to 12 hours.