Spectroscopic observations of the far-infrared [OIII] and [CII] lines present a pathway to explore the mechanisms of the emergence of massive galaxies in the epoch of reionization and beyond, which is one of the most fundamental questions in astronomy. To address this question, the Far-Infrared Nebular Emission Receiver (FINER) project is developing two wideband dual-polarization sideband-separating heterodyne receivers at 120-210 GHz and 210-360 GHz for the Large Millimeter Telescope (LMT) in Mexico. These receivers plan to provide an instantaneous intermediate frequency (IF) of 3−21 GHz per sideband per polarization, providing 40% of ALMAʼs light-collecting area and a similar atmospheric transmittance, but a five times wider bandwidth than current ALMA, offering a cutting-edge spectral scanning capability in the next several years. The project is currently in the active development phase, here we present the latest development status of FINER receiver at 210-360 GHz, including the wideband waveguide components as well as initial measurement result for the low-noise superconductor-insulator-superconductor (SIS) mixer.