Recently we used the CRM Manipulation Library for some Days related calculation.
To use it in CRM 2016, we updated the references to use latest SDK assemblies. You could download it form here.
While working with it we found a strange issue,
If we are using Add Days and we do not specify any value to Days to Add it will not perform any calculation. The workaround suggested was to add 1 Week and remove 7 days, something of that sort. Basically, we wanted to add 2 minutes here.
Thanks to this post for that
Hope it helps..