[3] Apostolov made his senior debut for the club as a first-half substitute in a 3–1 home win over Cherno More Varna on 13 March 2016.
[4] During the second half he was fouled for a penalty kick, which Lachezar Baltanov scored.
[5] Apostolov was loaned to FC Levski Karlovo for the beginning of 2016-17 season.
[7] On 25 March 2016 Apostolov was in the starting lineup of Bulgaria U19 for the 0-1 defeat from Belgium U19.
This biographical article related to association football in Bulgaria, about a midfielder, is a stub.