The pair both had been on month-long contracts with Leeds but neither will be offered an extended deal.
Former Leicester and Celtic winger Guppy made three appearances and scored in the 1-1 draw with Nottingham Forest at Elland Road.
Former Middlesbrough and Leicester player Hignett did not make a first team appearance and has since signed for Coca-Cola League Two side Darlington.
The 34-year-old Hignett quickly agreed a 12-month deal, with an option for another season, with The Quakers after they came out of administration.
"He came up here and it took about 10 minutes," said Darlington boss David Hodgson. He's a big plus for the club and the division."