Your comment made me want to check other FOSS messaging apps!
Briar — no push notifications. IRC - could not find foss client with push notification support (maybe you know one!) Delta chat — do not seem to provide the service themselves.
Briar — no push notifications. IRC - could not find foss client with push notification support (maybe you know one!) Delta chat — do not seem to provide the service themselves.
The project runs on a shoestring budget and has no problem delivering 15 million+ push notifications per month without charging the users any money
Briar allows you to run its Mailbox app on another device, giving you the tool to host your own notifications without building your own binary.
I know because I run both.