David Botterill has left the club and decided to move to Hythe Town.
The left-footed midfielder, 28, has been one of the longest-serving and most consistent players at the club.
He has recently struggled to get minutes on the pitch, due to the form of young midfield men Dan Carrington and George Monger.
The former Gillingham youngster surpassed 250 club appearances in September 2015.
Manager Ray Turner said: “I would like to place on record the club’s appreciation of the service, given by David Botterill.
“He has been a loyal and dedicated ever-present part of the team, since the Kent League days.
“He has decided now is the time to move on to a fresh challenge and we wish him well for the future.”
Once again, the club would like to place on record its thanks to “Botts”.