The midfielder joins Palace after impressing for Airdrieonians in their recent promotion to the Scottish Championship, the second-tier of Scottish football.
Devenny came through the ranks at Kilmarnock before moving to Airdrieonians on a permanent basis in the summer of 2022.
He made 54 appearances for the Diamonds over two seasons, notching five goals and seven assists. During their 2022/23 promotion-winning campaign, Devenny played 41 times, scoring in the penalty shootout of the League One play-off final against Hamilton Academical.