Since K2 Five 5.2 is coming up on end of standard support, we needed to migrate our 5.2 (Windows 2012, single server) to a Windows 2016 server environment. We also decided to take the opportunity to implement a server farm + load balancer + SQL Anywhere configuration for high availability. The entire process took way longer than I hoped and while K2 Support was very helpful, I would like to document my experience forr the benefit of the community.
Overall, I remain underwhelmed with K2 after so many years. The product team keeps pushing out patches and fix packs on a weekly basis but there are some fundamental issues with the installation & configuration that remain unaddressed year after year. This is very, very disappointing. I expect more from an enterprise platform like K2. With every major release, I look forward to a smooth upgrade but I have yet to be pleasantly surprised.
The K2 Five Designer is a disaster, I provided some feedback here. I don't see any major new features in 5.4, just minor tweaks.
Hope my experience helps someone.