Imminent (or already exceeded) expiry of a licence to use content such as a ringback tone is communicated by deliberately playing (9) modified content, such as by decreasing the quality of the original content. Quality of the content is gradually reduced during a grace period after T<SUB>expiry</SUB> (Fig. 1). The imminent expiry is communicated inherently in the content rather than in a separate notification, the content being modified (7) during the grace period in a manner to indicate imminent expiration. The automatic content modification has the effect of greatly reducing the number of content management messages transmitted in the network, reducing required bandwidth and network element processing operations. In audio content the player may remove frequency ranges by passing the content through a digital band pass filter.
