NGS has revised the CORS coordinates and absolute antenna calibrations. For a limited time, OPUS will provide access to both the current and previous frames. See FAQ & difference maps.
Which frame is best for me?
Most users should choose the current frames, using the previous only for NAVD 88 orthometric heights, or positions consistent with existing NGS datasheets. * note these will be superseded soon, when NGS completes the adjustment of the passive control network and release of GEOID12.
Why is there no NAVD 88 orthometric height for the current frame?
This is a temporary situation that will be resolved soon with the release of GEOID12 (see question above.) The current GEOID09 model was built from CORS96-derived ellipsoid heights, and therefore works best with the previous frame.
Will published solutions use the current or previous frames?
Either, for now, but soon all published solutions will be updated to the current frames, with previous coordinates retained as superseded.