Recommendation ITU-T G.7721 provides the management requirements and a protocol-neutral management information model for managing network elements and network of synchronization, based on the synchronization architecture and equipment defined in ITU-T Recommendations. Amendment 1 updates the Recommendation to align the information model for PTP telecom profile with the data set defined in [IEEE 1588-2019]. Amendment 2 to G.7721 updates the Recommendation to align the information model for PTP telecom profile with the latest editions of PTP Telecom Profiles Recommendations (i.e., [ITU-T G.8265.1] Edition 4.1, [ITU-T G.8275.1] Edition 4.2 and [ITU-T G.8275.2] Edition 3.2). This Revision updates G.7721 to align the information model for SyncPhy with the data set defined in [ITU-T G.781] Edition 5.2.