Solved Installed TailScale and now can NOT upgrade to v18

[bignetonline]

I SSH'ed into my GCP instance of 3CX and installed TailScale VPN so I could more securely and easily access my 3CX instance. However, when I went to upgrade the system to V18, it fails:

[31m[19:29] Preparation: Found an uncommon source list in /etc/apt/sources.list.d/: tailscale.list - 0[39m
> Execute apt command simulation on "install dphys-swapfile"
Reading package lists...
Building dependency tree...
Reading state information...
dphys-swapfile is already the newest version (20100506-3).
0 upgraded, 0 newly installed, 0 to remove and 14 not upgraded.
Reading package lists...
Building dependency tree...
Reading state information...
dphys-swapfile is already the newest version (20100506-3).
0 upgraded, 0 newly installed, 0 to remove and 14 not upgraded.

Is there anyway to fix this or a way to install TailScale but still upgrade to the latest system?

 

[NikosT_3CX]

@bignetonline we have never tested TailScale VPN so we are not in place to know what this will cause during upgrade this is why your upgrade rolled back and didn't it proceed.
What you may do is to ssh to the machine, remove from path "/etc/apt/sources.list.d/" the following "tailscale.list", clear cache and try again.
For secure way to ssh to your machine, you can allow via Google Firewall to be able to ssh to your machine via specific ip addresses only and also you may upload ssh keys to your instance.

Another way if you do not want to remove this source list, is to take a full backup, login to your portal and deploy a new machine with Debian 10 and v18 PBX directly, and then restore your backup on top of the PBX, port installation.