I have recently installed Ubuntu 17.04 on one of my computers and I noticed that differently from Debian 8.x with XFCE and LMDE 2 Betsy (Linux Mint based on Debian) with Cinnamon there is no system tray support on this OS.
I'm still able to see so-called indicators for Diodon, Touchpad indicator, Thunderbird via FireTray etc, but some relatively new applications such as Franz or Linux for Linux Beta still rely on system tray.
P.S. I'm currently using ppa:fixnix/indicator-systemtray-unity as workaround, but it sucks in both floating and static modes