Recommendation ITU-T G.874 addresses management aspects of optical transport network (OTN) elements containing transport functions of one or more of the layer networks of the OTN. The management of optical layer networks is separable from that of its client layer networks so that the same means of management can be used regardless of the client. The management functions for fault management, configuration management (CM) and performance monitoring are specified. Recommendation ITU-T G.874 (2008) updated the management information (MI) to align with Recommendation ITU-T G.798, reorganized the sections to align with the structure of Recommendation ITU-T G.7710/Y.1701, and replaced the generic text with pointers to Recommendation ITU-T G.7710/Y.1701. Recommendation ITU-T G.874 (2010) added the management of new transport functions that were introduced in ITU-T G.798 (2010), including OPSMnk_TT, OPSM/OTUk a_A, and ODUk for k=0, 2e, 4, and flex. Recommendation ITU-T G.874 (2013) added the management of hitless adjustment of ODUflex(GFP) (HAO), automatic protection switching (APS), application codes and performance management (PM) data collection. Recommendation ITU-T G.874 (2017) added a description to cover OTUCn GCC0, added the application code related MI signals, updated the MI signals for ODU2eP/FC-1200_A, OSM256.4/CBRx_A, OSx/CBRx-b_A_Sk and OSx/CBRx-c_A_Sk, removed the nDelay, nES, and fES primitives, moved the description of O.MN, O.MSN, and O.NE to the convention clause, updated the default values of DEGThr and DEGM, updated Appendix III to align with Table 15-9 of ITU-T G.709/Y.1331 (2016), and removed the adaptation function activation and MI_Active to align with ITU-T G.798. Recommendation ITU-T G.874 (2020) aligns with the latest editions of ITU-T G.709 and ITU-T G.798, and harmonizes generic requirements with clauses 8 and 10 of ITU-T G.7710/Y.1701. Recommendation ITU-T G.874 (2022) aligns with the latest editions of ITU-T G.709 and ITU-T G.798, including their amendments.