When I say "Synology," the first thing that comes to mind is personal servers, NAS, and lots of cool things you can keep stored on your own "cloud" to access anywhere and without trusting any company with your data. Now Synology is using its expertise in building personal servers and apps to introduce an instant messaging application.
In a world where privacy is a big concern and end-to-end encryption is more and more important, having your chat app run off your own server saves you the trouble of researching whom you can and can't trust with your data. It may not be ideal for communicating with everyone you know, but it's an interesting solution for the friends and family you trust, especially if you already have a Synology server.
The app looks pretty barebones right now. There are channels, users, stickers, comments, and... well, that's what's apparent in the screenshots. And one Play Store reviewer has pointed out that notifications aren't working on Android.
In order to install the Synology Chat server, head to your DSM's package manager, enable Beta support in the settings, and then search for "chat":