Stevenage striker Taiwo Atieno has left Broadhall Way after coming to the end of his short-term contract.
The Kenya international, who started the season at Luton Town, scored five goals in 17 games for the Hatters.
But, after being released from Kenilworth Road, the 25-year-old has made just one Boro start since signing a three-month deal in February.
Meanwhile striker Michael Thalassitis has been handed a two-year deal at the club.
The 18-year-old is the first product of the burgeoning Stevenage centre of excellence to receive a professional contract.
"It's my first club, I've never had a contract before," he told the club website.
"I was really happy when I was told I would be going in with the first team. I went in to try and earn myself a contract and that's what I've done."