I have found another more user friendly way.

I have installed the SFTP plugin into Total commander and I set up a connection using the other device's IP address (172.28.172.2). This way I can browse the other device like a local folder and copy/paste files from and to it easily.
What is interesting though with this solution, while TC on the host device cannot "see" outside of the android "box", the target device where I sftpd in shows everything, including the sailfish os root.

My next other idea is mounting the other device into a folder. (I am using the cifs package from openrepos for this to connect to my NAS at home when I need.) If this is required to run a samba server on the target device, for Android there is a free one in google play store that supports SMB and CIFS.) Plus there is the JuiceSSH app in there so the connection via ssh should also work on Android too.

I know this is not so universal as bluetooth but I think it is more secure as you only turn any of these on if and when you need, while a bluetooth can be left on. (Although a switched on bt might not be an issue, I don't know as am not good at hacking.)

Well, I only use bluetooth once in a while to share pictures or videos from phone to phone and this functionality can't be replaced with other hacks
In the Sailfish version I used before (2.0.4.13 based on CM12.1 from @mautz) bluetooth file sharing worked as expected.

I understand what you are saying.
If this worked before, then probably it can be fixed. I am happy to do that but probably will need some support from mautz to know what to change.
Are you aware whether the bluetooth file sharing works on the other sailfish os with cm13 base?

Perhaps I missed something but is there any way to get Alien Dalvik (or equivalent) installed for running Android apps?

Sorry, I'm new to Sailfish OS.

It's in the first post, see the instructions for sfdroid. I don't know how well it works but the CM11 base one works pretty well iirc. Was years ago I used it though.
https://wiki.merproject.org/wiki/Ada...for_hammerhead

Please follow the instructions of edp17 and install its latest version of Sailfish OS https://talk.maemo.org/showpost.php?...&postcount=785

For Alien Dalvik and Android apps yes, it works without camera and videos in android apps (if you try to play a video within an android app it will crash). Apart from that, I am using Whatsapp, Telegram, Here maps and some others and their running fine. With the first two voice calls works too.

The package was created by the user @matemana and published here.
but the file is not present anymore, I have reuploaded it here.

You can just download and install as it is, first allow untrusted sources in Settings.

Keep in mind that Alien Dalvik is shareware and officially not available on ported devices. On the other hand, if you have paid a Sailfish licence I would not be worried, it's your choice!

Thanks for the updates. I think I'll check out sfdroid.

Experimenting is always good!
But SFdroid works only with the old SFOS 2.0.something. If you would like to use Sailfish I suggest you to get a recent version, because many apps have been updated and work only with newer releases of the OS.

I have tried all available SailfishOS versions and SFDroid and AD combinations and I ended up building a new image with the 12.1 base because SFDroid was not really ready for daily usage.
However as you said, through those experiments I have learnt a lot and it was fun too.

@mautz: I have a bad news about the Anbox. BirdZhang has stopped working on it.
This means for the 14.1 base there won't be support anymore. I know you are not really interested to the Android support but it may impact your work with the 14.1 base.