Recommendation ITU-T G.8275.1 specifies a profile for telecommunication applications based on the precision time protocol (PTP) as defined in IEEE 1588. The profile specifies the PTP functions that are necessary to ensure network element interoperability for the delivery of accurate phase/time (and frequency) synchronization. The profile is based on the use of full timing support (FTS) from the network architecture described in Recommendation ITU‑T G.8274 and definitions described in Recommendation ITU‑T G.8260. Common aspects of PTP profiles for phase/time synchronization are specified in Recommendation ITU‑T G.8275. This amendment of Recommendation ITU‑T G.8275.1 provides the following changes: Enhances Annex M. Enhances Annex N. Adds editorial enhancements throughout the document. Updates clause 5, referring to new ITU-T Recommendations in clause 2. Adds a note in cause 6.2.8. Adds a note in clause 6.3.7. Increments profileVersion and profileIdentifier in clause A.1 and A.11. Adds a note in Table A.5. Adds a note in Table N.1. Updates N.2.1.