Self-hosted servers using a private certificate authority — mkcert and similar — now work over https. Install your CA on the device and Prism will trust it. Previously only certificates from public authorities were accepted, so LAN-only setups had no option but plain http.
About Prism
Prism is a UnifiedPush distributor that uses Mozilla's push server for transport. It optionally pairs with a self-hosted Prism server, which can monitor your Proton Mail inbox and route notifications to Signal, Telegram or this app.
The Prism server also accepts notifications from any source via a webhook API compatible with ntfy.