Anyone here using S to collaborate with others on non-cloud Android calendars?

I’m trying to utilise Syncthing to one more non-standard use case which is to syncronise offline (local) Android calendars between multiple devices/collaborators (without utilising cloud or PC, just smartphones).

Before I jump into setting up my own scheme, I’m wondering if someone has already found a working robust solution.

Anyone, please?)

I’m not that familiar with caveats, but I would start with Etar as Calendar app (with local calendar capability) and “Calendar Import-Export” (to handle export/import via ics).

Just in case, I’m familiar with How to sync contacts and calendars between desktop and Android (without root) , but as it involves termux and local server (radicale) that are not best friends of Android’s power management, I’m looking for other solutions before I give up)

Honestly, I don’t think they actually have any meaningful impact on the battery life at all. The reason is that Radicale only triggers if it detects changes in the files, so if there are none, it just sits there in the background doing nothing. Termux is only used to run Radicale, so it also doesn’t use any battery on its own. DAVx5 does use some battery when it syncs, but it all depends how frequent the sync interval is.

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Tnx. I was also thinking about 2nd part of the story where Android kills background apps. I understand it also applies to other backyard apps like syncthing, but I couldn’t yet figure out if Android treats “native”))) apps differently from termux-like stuff.

But as I also want to handle contacts “locally” in the future and there are no apps that are even close that allows what I’m looking for, maybe I will anyway try phone-hosted now and will consider file-baser stuff for calendar later.

So to others, if by chance you have working solutions for the originally described topic, may I ask you for 1 minute of your time to describe? Thank you!

Normally, Android shouldn’t kill an app as long as it displays an ongoing notification (i.e. a notification that cannot be cleared). When using the linked solution, both Syncthing and Termux end up displaying ongoing notifications, so that the OS should not kill them.

Please take into account though that Android may still kill such apps anyway if it runs out of RAM. Also, if the OS comes from a specific phone manufacturer, then additional tweaks may be required to prevent the apps from being killed (see

Thank you for recommendations. This is going off topic, so I would wait for others to see if there are any other solutions possible.


As we’re talking about smartphones, I think it’s still worth to seek for balance between functionality and battery drain, so I tend to be restrictive here. Beside me and my scripts, there also may be bugs in SW that will eat the remaining battery at a wrong time)). An example is that though I’m using Tasker for some limited automation, I rely on Bixby routines to trigger Tasker. I believe) Samsung may be paying more attention into optimisation of Bixby routines to preserve positive customer experience re Samsung ecosystem. I acknowledge that so far I have not seen/found any evidence that would support my claim re optimisation, so maybe I’m overcomplicating it.

Thank you very much for your guide, I’m trying it now! It looks like it will save me from hassle with contacts app

I would use DecSync CC for this, without Radicale. It supports Android local calendars and contacts, synced via Syncthing - i.e. exactly what you’re looking for.

Thank you for the advise. I had it on my list. But I’ve put it aside because of it’s “above average” risk to become abandonware.

Both CC’s last release (as well as it’s parent DecSync) is dated Dec’21 + no active conversations in Issues section.

Just in case, I’m looking for a protected solution here, one that in that way or another allows to keep contacts info away from apps (except for those who are granted Contacts permissions of course and can thus fetch it from Android address book).

Well, it works fine for me, including in Android 14, but I understand being wary. Is the project still active? · Issue #93 · 39aldo39/DecSyncCC · GitHub suggests it’s still maintained.


yep, the msg you’re referring to is back from Mar’23 ) if one would ask today, I would assume the answer could be the same, but similary to OpenContacts (that no longer registers itself in Android 12 as a dialer app), I would prefer combination of clearly alive tools to the better suited one but with quite few contributors and close to none activity in “community” sections (it’s rarely a sign of “it just works nothing to discuss” for similar prjs).

The cost of trying some solution for my particular setup, (checking for compatibility, caveats, bugs, etc) is too high to through on higher risk solutions.