Just got the new 9.4.0 build 4174-29 a couple days ago in my Ultra (4640x), and have been getting a power or app logout around 4 hours of streaming. Now, there used to be a 'system/power' with a 4 hour time setting (still there on my 9.3.0 roku4's) but has dissapeared on 9.4.0, but is seems that the programmers have decided to make it non-selectable with the new os (?). Not good. Was this checked before rollout? Don't think so. Maybe older sets and newer ultras dont have this problem, but my 3 roku4's haven't gotten the upgrade and I only have the one ultra/4640x. So I wonder what gives.
Are you speaking of the "Bandwidth saver" under Settings->Network? Perhaps the update enabled it.
No. There used to be another limiter in 9.3.0 that was 4hrs, but in 9.4.0 is has been removed. I checked the bandwidth saver (it was set to off) and toggled it on and then back off, to no avail. After 3-4 hours the unit exits out of the running app, no questions asked. Once or twice the last couple days it exited to a blank screen, the only way to regain control was to press either the back button several times or the home button; if it happend more times I'd know which one worked.