Syncing notifications between multiple devices

[Ing. Bernhard Polt, MA @ TILDE GmbH]

Dear all,

First, I'd like to thank all of you, who dedicate their time and skills
to this awesome piece of software.
It's one of the most helpful tools in my Linux-Android-Environment.

Now, as I have observed some "issues" related to the syncing of
notifications across devices, I thought it's best to get in touch with
you.
The following might get a bit long (sorry for making you read so much -
I just think it's better to clearly describe some things up front
instead of making you ask again and again). Therefore, I decided to
push the description of my setup to the bottom of this message and
present my questions first.

Question A: how does the Linux plugin for "send notifications" decide
which applications are available for selection for each device?

Question B: in the Linux plugin for "send notifications": what is the
"black list" for?

Question C: in a setup which includes a Linux system, an Android phone
and a smartwatch connected to the Android phone (for details see
description below) - why do notifications sent with kdeconnect-cli from
Linux using "ping" or "ping-msg" get forwarded to the smartwatch, while
all application notifications remain on the Android phone without
notifying the smartwatch?
After lots of testing and reading and reading and testing - my guess
is: it has something to do with the notification's "urgency", thus the
following additional questions:

Question D: what is the notification urgency of a "ping" or "ping-msg"
when using kdeconnect-cli?

Question E: is it possible to change the notification urgency of a
"ping" or "ping-msg" when using kdeconnect-cli?

Question F: on the Linux system, is it possible to "override" the
notification urgency of an application's notifications with a selected
value?

Furthermore:

Question G: on Android with multiple users - where each user is running
KDE connect app simultaneously (see description below) - why does the
currently logged-in user NOT get a notification from the Linux system,
while the user "in the background" does receive the notification?
(further clarification: this behaviour does not depend on whether the
user is a privileged main-user or a sub-user with certain restraints:
when logged-in as main-user then the sub-user receives the
notification, when logged-in as sub-user then the main-user receives
the notification)

Question H: video-playback-control across devices is awesome -
especially as it even works from my Pixel Watch 2 (see description
below)! In the Android app, it's great that it's even possible to
switch between players when one device is running multiple players
simultaneously.
Having the playback-control on the notifications-screen is very handy.
Unfortunately, I didn't find a way to choose between different active
players here. Instead of just displaying one distinct playback-control
here (I guess it's usually the one which was startet earliest, but
didn't test in detail yet), is it possible to show one tile for each
playback? Possibly even grouped by device?

I'd be happy to provide any further information if needed.
I'd even run tests on my setup if it helps you and your project.

Best regards from Austria,
Bernhard


PS: Now here a "brief description" of my setup (I'll try to keep it
short - if required, I'm happy to provide more details):

I use multiple laptops running Linux-Mint including KDEconnect as well
as the "kdecapplet at joejoetv".
Also, I use multiple smartphones running different versions of Android:
Nexus 5 on Android 6.0.1, Nokia 8 on 8.1.0, Pixel 8 Pro on latest
GrapheneOS (Android 14) - all of which running latest KDE Connect app
as well as RethinkDNS from F-Droid store.
Now, I know: using RethinkDNS (mostly for blocking tracking) can be
troublesome for an app like KDE connect. But I'm able to set it up just
right so all devices can find and connect with each other. (although,
the VPN-settings on each device need to be slightly different - which I
guess is due to the differences in the VPN-implementation of the
different Android versions, but that's not something I want to explain
in details here and now, unless you guys aks for it...)

One more device is a Pixel Watch 2, which is connected to the Pixel 8
Pro via Bluetooth but also has access to the same WiFi.
Now, on the Pixel 8 Pro with GrapheneOS, I try to encapsulate the
Google-services as good as I can. Therefore, I installed the F-Droid
store (and any app from there) as the main-user, pushing the apps to
the other users (this includes the KDE connect app).
I don't have the connection to the Pixel Watch 2 as the main-user,
because it's missing the Google-services. Therefore, I have another
user which has the Google-Services and some Google apps installed (but
selected carefully and with very limited internet access thanks to
RethinkDNS) - in order to achieve that, this user also needed a Google
account. But I didn't forward the account credentials to the Pixel
Watch 2, which means it's running without access to a Google or Fitbit
account (I know, seems pointless as most of the functionality requires
either one account - but I want to figure it out that way...).
However, in the "Google Watch" app I chose to forward to the Pixel
Watch 2 as many notifications as possible.

As for the KDE connect notification settings on these devices: I set
everything for maximum syncing (all devices "send to" and "receive/sync
from" every connected device for every available app).
Here I noticed something strange on the laptop side plugin settings for
"send notifications": each device shows a different list of
applications. While for the Nokia 8 (which holds a lot of apps) I can
tick the ckeckboxes for laptop applications like Signal, FileZilla,
uGet or blueman (amongst many others), for the Pixel 8 Pro I can tick
only uGet and Signal (amongst few others), although there is no Signal
app on the Pixel 8 Pro but it does have Bluetooth (yet blueman is not
offered). Also, the main-user on the Pixel 8 Pro is running it's own
instance of KDE connect simultaneously to the "Google services enabled"
sub-user. Thus, there are two Pixel 8 Pro devices connected to the
laptop (as well as all other devices - they are even connected with
each other, which means I can share & sync between main-user and sub-
user!). Although being the same hardware and software (at least most of
it - see above), the application lists available on the Linux laptop
are different.