The 32-year-old striker played 76 times for Boro after joining from Cambridge in 2008, scoring 23 goals, but he was restricted to just two appearances this season due to injury.
Boylan started his career with West Ham and has played for a number of clubs during his career including Exeter and Canvey Island.
His successful spell at Canvey Island saw him hit 135 goals in 157 appearances.
Source: PA
Source: PA