I get a NMEA stream exported from Applanix PosPac in the epoch the measurements took place (2019). These coordinates go into a software, that interprets the NMEA Lat Lon as EPSG:4326 with Proj4 library. From there, I export georederenced point clouds into another coordinate system, the software does the conversion from EPSG:4326 into the desired system, e.g. UTM ETRS1989 EPSG:25832, using Proj4. If I understand correctly, Proj4 must implicitly assume an epoch for the WGS84/EPSG:4326 system.
Is this epoch 1984? Or has there been an update for the WGS84 standard epoch? I can export lat lon at any epoch, so I just need to know which one is correct.