Paul joined Reds in May 2012 on a two-year deal after leaving Championship club Peterborough United, where he was a virtual ever present for Posh in the 2011-12 campaign.
The keeper started his career at Leyton Orient before joining his former youth-team boss Alex Inglethorpe when he took over at Conference side Exeter City.
Paul became the first goalkeeper to save a penalty at Wembley in the 2007 Conference play-off final before keeping a clean sheet in the final 12 months later as Exeter returned to the Football League.
Paul made 158 appearances for Exeter before joining Posh in January 2011 and establishing himself as first choice at London Road.
In his first season with Reds Paul was first choice and made some important saves, including two from penalties when Reds knocked Millwall out of the Capital One Cup with a shoot-out win at the New Den.
He finished the season as an ever present with 54 appearances in league and cup.