The physical constants built into LabVIEW 2018 are based on the older, 2014 definitions of the fundamental units. The recent redefinition has generated a change in most, if not all physical constants, and these are reflected in the 2018 constants published by CODATA in July 2019. The constants are made available in ASCII form and I've automated the generation of subVIs to make these available directly within LabVIEW.
All of the VIs have the value in extended precision, with the correct unit. The second output has the measurement error should you need it.
Hardware and Software Requirements
(Let me know if you'd like it in 2017)
Steps to Implement or Execute Code
Copy the llb in to a convenient place such as the user.lib folder and refresh the palettes. Unfortunately, as there are so many VIs, the palette view is too large for the screen. Pin the palette and switch into text mode so that you can scroll through them all. Quickdrop will find them too if you know the names.