Hi @amers, thanks for your reply and yes I assume that the messages can somehow exported and imported on this way but the media stuff will be gone.
Here is how I resolved it on my own.
From my perspective there is no way around a re-register (unregister under gcm and register the websocket version) what will lead to a message like
Safety number has changed
at your contacts in the the conversation with you.
What you need:
- a smartphone which is able to communicate with Google Cloud Messaging (GCM) Services --> this can be:
** a old phone which has Play Services installed (in case you would like to migrate to a google free new smartphone) or
** the same phone where you would like to uninstall all Google related services (like in my case a system with a working mircoG installation which is able to contact GCM) and go on with Signal websockets version - at least at the beginning of the procedure GCM has to work without any problem (later you will uninstall it of course).
a working backup recovery tool for your android version (as explained I prefer oandbackup but Titanium Backup and so on should work as well) --> at least it should be able to backup and restore data of apps
- if you use two phones (like I did as microG was not fully working on my “new” phone after an Upgrade anymore) the backup tool should of course work on both and you need a possibility to transfer the Signal Data backup from one to the other. (microUSB-Stick, adb, syncthing, … what ever works for you)
- The phone where you want to do this should be rooted and run a custom rom of course (like FP Open in my case) - otherwise a lot of the steps might not be possible
Procedure (doing everything on one phone):
- on the phone where your Signal Installation, with a working GCM communication and with all your data you would like to keep, is running unregister from Signal messages within the App (Settings -> Advanced -> “slide” Slider “Signal messages and calls” to the left and agree) … the whole thing is most easy if GCM communication still works on the same phone where you would like to switch to no Google Services (uninstall) and websocket version of Signal.
perform a backup - at least data - of the Signal App. (in my case the backups will be stored under:
/storage/emulated/0/oandbackups in addition most of these tools provide a possibility to change the “backup-to” and “restore-from” path)
uninstall Signal and remove everything which has todo with the communication with Google Services (gApps or like in my case microG)
re-install Signal again (use the websocket supporting version - you get it here: https://signal.org/android/apk/ I cannot ensure if websockets will work with a version you get e.g. via yalp store)
restore the data-backup you made under step 2 (it is better when the Signal App and the background process for websockets is not running - if this is the case go to Apps under Settings of your phone and “force (Signal to) stop”)
- start Signal (if your messages and media store was encrypted by a password before you will be asked for it as normal)
register for Signal messages again - within the App (Settings -> Advanced -> “slide” Slider “Signal messages and calls” to the right; Type in your number and agree/register)
Congratulations Signal is running with websockets now and you did not lose any of your messages or media-stuff you had before.
Why I used two phones to reach my goal? (this should be helpful for a migration from one to another phone):
I stuck at point 1 as microG was not fully working anymore (on my Fairphone 2 after the upgrade). Signal crashed everytime I tried to unregister (I assume the reason it it has to communicate with GCM to unregister - if this is not working it leads to a crash … just an assumption).
Even working around this with unregister via website - Signal offers such a possibility https://signal.org/signal/unregister/ - did not help as the data backup was from a “GCM version registered App”.
So I had to move my backup to my old phone with gApps installed (a Nexus 5 with CyannogenMod) and restore it there --> unregister --> backup again and move the un-registered backup back to my Fairphone.
While writing this @Roboe updated this topic as well and I see that pm might be another possibility to move the “Slider” for registration on this level. I did not try this yet but this might obviate the need of a second phone. Thanks @Roboe.
Maybe this also provides a way around the necessity of the re-register in general.