Embodiments include methods for notifying of changes to an access network's (AN) compliance with a QoS requirement for a data flow between an application server and an application associated with a user equipment served by the AN. Such embodiments include receiving, from a core network (CN), a first safeguard time associated with the QoS requirement and representing an amount of time required, prior to AN non-compliance with the QoS requirement, to adapt the application for safe operation during the AN non-compliance. Embodiments also include determining that, at approximately a first instance in the future, the AN is likely to be non-compliant with the QoS requirement; and sending, to the CN, a first notification indicating a likelihood of future AN non-compliance with the QoS requirement. The first notification is sent at least the first safeguard time before the first instance. Embodiments include complementary methods performed by CNs and application servers.