Christopher Grenfell crushed James Simpson to death outside his home in Ashgill, Lanarkshire, last November.
Grenfell was found guilty of Mr Simpson's murder in August and jailed for a minimum 17 years after a trial at the High Court in Glasgow.
The unemployed 25- year-old claimed he had killed Mr Simpson "by accident".
The Court of Appeal in Edinburgh yesterday confirmed Grenfell's legal team last week lodged papers to challenge the conviction.
No date has yet been fixed for any possible hearing.
Grenfell denied he had "set out" to kill the pensioner that evening and offered to plead guilty to culpable homicide.
Judge Lord Burns told Grenfell the killing was "deplorable" and "motivated by greed".