After three weeks of trying all the router settings in this post, trying cabled 5ghz, 2.4 ghz, downgrading to 1.5 then 1.3.1, re installing Java, trial and error with different startup devices, removing all devices except the LG tv and the streaming device I am giving up.
I have used Serviio for 5-7 years (somewhere in between) and had no problems but after upgrading to 1.5.2 with no network changes it keeps now dropping off constantly some changes have made the drop offs more often and sometimes it seems around the 30 minute mark.
I am an IT senior consultant and am pretty sure that this is a fundamental flaw in the Serviio product code. Maybe the changes in this post have helped work around a problem for some people but I feel an undercurrent or an issue with the product exists. At the very least some mechanism is required that does not currently exist should be telling us where the core disassociation or drop off exists.
I have today installed Plex and everything is working normally again with my network, router, firewall and switch all back to where they were before the upgrade to 1.5.2.
I recommend anyone that has this problem to try Flex as it works.
Signing off from Serviio unfortunately frustrated.