Brian Howard (Howard) timely appeals the summary denial of his motion for post-, conviction relief filed pursuant to Florida Rule of Criminal Procedure 3.850. In his motion, Howard alleged his plea was rendered involuntary by the 1996 amendment to Florida Administrative Code Rule 33-11.0065, which applied retroactively to deny him the ability to earn incentive gain time. We affirm as this claim does not state a claim cognizable in a postconvietion proceeding. See McConnaughy v. State, 684 So.2d 851 (Fla. 5th DCA 1996); Washington v. State, *993683 So.2d 215 (Fla. 4th DCA 1996). Our affirmance is without prejudice to Howard seeking mandamus relief in circuit court, if necessary, to require the Department of Corrections to restore his incentive gain time in accordance with Gwong v. Singletary, 683 So.2d 109 (Fla. 1996).

AFFIRMED.