Hello everyone,,
I have updated to Plasma 5.16 through Kubuntu Backports and is working great but there are two weird issues since I updated:

File transfer notifications are gone (ironic, because I heard they made improvements on that), instead I get a separate window for file transfers (even though I did not have that enabled).

(EDIT: Solved by updating KDE Frameworks) The Oxygen DSX theme has a missing white border on panels, I can make it show again if I switch to any other theme and then switch back again to Oxygen DSX (the issue is there again when I restart Plasma). It actually shows a line of the background when apps are maximized.

Has anyone experienced similar issues? Should I bug report it?

if you are a contributor, you should have a more recent Plasma, 5.16 is pretty outdated now