[SahAssar]

I guessing that is because it wants to work without google play services so it needs to keep a connection to the server. This is similar to how signal works when run without gApps.

[JasonFruit]

I don't have problems with battery life running Signal without GApps or MicroG.

[gsich]

Same. I don't see how a connection to random server X should eat more battery compared to Google.

[mkeedlinger]

I think the difference is more that each app has to maintain its own connection (more connections, more drain). Seems like gotify could remedy that though.

[avinassh]

TIL. How does Signal sends push notifications without GCM?

[MayeulC]

Just like how google services handle push notifications on your phone: a persistent connection.

Without GCM though, every app needs to maintain a separate connection, which drains more battery.

That's why we need more alternatives to GCM, like UnifiedPush.