Migrating Android app data

• Transfer Signal using Signal-native Backup and Restore
• Transfer WhatsApp by copying the internal app files
• Transfer Threema/ThreemaLibre data with native backups

Transfer Signal using Signal-native Backup and Restore

The best source to install Signal is always direct from the website https://signal.org/android/apk/#target 

Export on the old phone

Open the Signal app and go to the settings. Navigate to Chats and then Backups (at the bottom). If they are disabled, turn them on.

Note down the passphrase, you'll need it for the restoration!

Data transfer

Import on the new phone

Starting Signal the first time, it asks you if you want to set it up newly or restore from a backup.

On the next screen you will be asked if to restore from another device or from a file. Chose the latter:

On the next screen click the button "Choose backup":

This opens the native Android file chooser. With the button top left you can switch between internal storage and memory card.

Choose your backup file.

The next screen will show you a few meta information on the file (age, size):

Tapping on "Restore backup" will ask you for the passphrase:

Now, the restoration is in progress:

Guide to be continued.....

Transfer WhatsApp by copying the internal app files

As of 2025, the default method of WhatsApp to Backup and Restore requires a Google Account and Chat data transfer using local Wifi requires Android features that are not available on Sailfish OS.

You will need to have the developer access enabled (access via SSH) and system administration experience is of good value.

We start on the old phone:

• Turn off Android: As a first step, open the Settings App, go to System, and select Android™ AppSupport. Tap the Stop button and wait until he action is completed.
• Open Terminal or Login using SSH
• Enter devel-su
• Run tar -czf /home/nemo/whatsapp.tgz /home/.android/data/data/com.whatsapp/
• Transfer the resulting file to the new phone

Then, continue on the new phone:

• Start WhatsApp once and stop it again
• Open the Settings App, go to Apps, select WhatsApp and delete the data and clear the cache.
• The, still in the settings switch to System, and select Android™ AppSupport. Tap the Stop button and wait until he action is completed.
• Open the terminal and enter devel-su
• Run ls -ld /home/.android/data/data/com.whatsapp/ and remember the owner and group ids. They both are the same and likely look like 100XX.
• Delete the existing directory rm -r /home/.android/data/data/com.whatsapp/
• Run cd  / && tar -xzf /home/nemo/whatsapp.tgz
• Reset the permissions as read before: chown -R 100XX:100XX /home/.android/data/data/com.whatsapp/

Now start WhatsApp and enjoy!

Transfer Threema/ThreemaLibre data with native backups

Either Cloud backup or local backup

The cloud Backup does not include the chat contents!

Just transfer the archive from one phone to the other.