currently using Horizon client version 2103 (8.2.0), system management suggests switching to 5.5.2.
But this seems like going back to an older version? Although 5.5.2 has newer release date then the 8.2.0 version.
What is the difference between them? Why would I switch from 8 to 5 (although 5 seems newer).
Did you check Product Interoperability Matrix?
Maybe this is the reason depending on your environment.
I would check if upgrading to 2106 is a better option.