No attendance requirement.
I did a little bit of research. It appears the requirement for attendance at communion to maintain membership was removed in 1986, and the requirement to record attendance was removed from the Book of Forms in 2003.
REG MCMILLAN, ONLINE
Section 125.5 of the Book of Forms states in part: Members who have not been faithful in their attendance at worship services and have ceased to participate actively in the life and work of the congregation shall be contacted, visited where possible, and encouraged to renew their commitment to Christ and his church. Where possible, such persons should continue to receive pastoral care. ...