Recommendation ITU-T G.875 (ex. ITU-T G.874.1) provides a protocol-neutral management information model for managing network elements in the optical transport network (OTN). The model contains the managed entities and their properties that are useful for describing the information exchanged across interfaces defined in the ITU-T M.3010 telecommunication management network (TMN) architecture. The protocol-neutral management information model shall be used as the base for defining protocol-specific management information models, for example, common management information service element (CMISE), common object request broker architecture (CORBA) and simple network management protocol (SNMP) information models. Mapping from the protocol-neutral entities into protocol-specific objects is a decision of the specific protocol modelling design and should be described in the protocol-specific information model Recommendations. Amendment 1 adds the UML information model for fine grain OTN (fgOTN), in alignment with the management requirements defined in ITU-T G.874 (202x), ITU-T G.798 (2023) Amd3 and ITU-T G.709 (2020) Amd4. It also aligns the UML information models in this Recommendation with v5.0 of the ITU-T Core UML information models, defined in ITU-T G.7711 (08/2025), the v1.3 of the Medial layer UML information models, defined in ITU-T G.876 (2021) Amd3, v3.1 of the ITU-T Ethernet UML information models, defined in ITU‑T G.8052 (2024) Amd1, and v4.1 of the ITU-T MPLS-TP UML information models, defined in ITU-T G.8152 (2024) Amd1.