Just sharing experience with Custom Visual Process Flows and Flash on Server 2016 (not relevant to back end server, only Terminal / Citrix servers with local users):
Client has new server and since buying new license bought 2016. Needs Flash for Sage's Visual Process flows, so had to figure out how to install.
Likely already known by many here, in Server 2012 R2 can add via Features -> User Interfaces / Features -> Desktop Experience (doesn't mention Flash, but adds it). Not there in Server 2016.
Server 2016 (from command line run as administrator):
dism /online /add-package /packagepath:""C:\Windows\servicing\Packages\Adobe-Flash-For-Windows-Package~31bf3856ad364e35~amd64~~10.0.14393.0.mum""
Reboot.
This will add Flash, but the other piece (back end server related) is the Custom Visual Process Flows do not migrate via migration utility, at least they didn't this time (my first to do this as part of upgrade). They can be found in the MAS_SYSTEM\VPF folder (.vpt files), will need to manually copy custom ones to new install.
Hope this helps someone in the future.