F-droid builds everything from source so there would have to be a build flag that would remove GCM functionality. From what it looks like, when GCM is disabled, vector reverts to polling the server for information instead of messaging interrupts[0]. This is of course highly inefficient and an alternative has been proposed in the issue, but I can't speak to it.
It looks like the team previously made Google Analytics opt-out-able[1]. I didn't look at the commit to see if it's a build flag or just a GUI toggle. I believe to be on f-droid it would have to be absent the binary entirely.
I found an issue relating to allowing a GCM opt-out[2]. I think this would realistically require the polling issue to be solved though.
Here is the f-droid request for addition[3].
I'm not sure about a solution and all I've done is comb the issue log a bit. The Conversations app currently on F-droid is able to handle timely messaging with low battery consumption and no GCM. They're different protocols entirely, I realize, but maybe some ideas can be gleaned from that implementation. In a perfect world, all open-source decentralized applications would depend on zero closed-source centralized services, but I know the cost/benefit analysis of the implementation overhead may not always weigh out.
It looks like the team previously made Google Analytics opt-out-able[1]. I didn't look at the commit to see if it's a build flag or just a GUI toggle. I believe to be on f-droid it would have to be absent the binary entirely.
I found an issue relating to allowing a GCM opt-out[2]. I think this would realistically require the polling issue to be solved though.
Here is the f-droid request for addition[3].
I'm not sure about a solution and all I've done is comb the issue log a bit. The Conversations app currently on F-droid is able to handle timely messaging with low battery consumption and no GCM. They're different protocols entirely, I realize, but maybe some ideas can be gleaned from that implementation. In a perfect world, all open-source decentralized applications would depend on zero closed-source centralized services, but I know the cost/benefit analysis of the implementation overhead may not always weigh out.
Keep up the good work either way.
[0] https://github.com/vector-im/vector-android/issues/167 [1] https://github.com/vector-im/vector-android/issues/61 [2] https://github.com/vector-im/vector-android/issues/87 [3] https://f-droid.org/forums/topic/vector-a-polished-matrix-ch...