A method performed in a User Plane Entity, UPE, in a core network of a cellular communications system to perform a user plane requested, Packet Forwarding Control Protocol, PFCP, association release procedure, the method comprising: • for each PFCP session of one or more PFCP sessions affected by release of a PFCP association: ∘ sending towards a Control Plane Entity, CPE, a PFCP session report request for the PFCP session, the PFCP session report request comprising: - one or more non-zero usage reports for the PFCP session; and - an indicator which indicates that the PFCP session is being removed and that the one or more non-zero usage reports are the final for the given PFCP session; ∘ receiving a corresponding PFCP session report response message for the PFCP session sent by the CPE to confirm the receiving of said final one or more non-zero usage reports for the PFCP session; and ∘ deleting the PFCP session at the UPE; and then • sending towards the CPE a PFCP association update request that requests the CPE to release the PFCP association, which PFCP association update request comprises an indicator which indicates that all non-zero usage reports for the one or more PFCP sessions affected by release of the PFCP association have been reported; • receiving a PFCP association update response returned by the CPE; • receiving a PFCP association release request sent by the CPE; • deleting any remaining PFCP session; and • sending a PFCP Association Release response towards the CPE. • for each PFCP session of one or more PFCP sessions affected by release of a PFCP association: ∘ sending towards a Control Plane Entity, CPE, a PFCP session report request for the PFCP session, the PFCP session report request comprising: - one or more non-zero usage reports for the PFCP session; and - an indicator which indicates that the PFCP session is being removed and that the one or more non-zero usage reports are the final for the given PFCP session; ∘ receiving a corresponding PFCP session report response message for the PFCP session sent by the CPE to confirm the receiving of said final one or more non-zero usage reports for the PFCP session; and ∘ deleting the PFCP session at the UPE; and then ∘ sending towards a Control Plane Entity, CPE, a PFCP session report request for the PFCP session, the PFCP session report request comprising: - one or more non-zero usage reports for the PFCP session; and - an indicator which indicates that the PFCP session is being removed and that the one or more non-zero usage reports are the final for the given PFCP session; - one or more non-zero usage reports for the PFCP session; and - an indicator which indicates that the PFCP session is being removed and that the one or more non-zero usage reports are the final for the given PFCP session; ∘ receiving a corresponding PFCP session report response message for the PFCP session sent by the CPE to confirm the receiving of said final one or more non-zero usage reports for the PFCP session; and ∘ deleting the PFCP session at the UPE; and then • sending towards the CPE a PFCP association update request that requests the CPE to release the PFCP association, which PFCP association update request comprises an indicator which indicates that all non-zero usage reports for the one or more PFCP sessions affected by release of the PFCP association have been reported; • receiving a PFCP association update response returned by the CPE; • receiving a PFCP association release request sent by the CPE; • deleting any remaining PFCP session; and • sending a PFCP Association Release response towards the CPE.