...

Installation process for FreePBX 16.0 ISO would be same as our existing disto installation. Please refer to - Installing FreePBX with the Official Distro 

Older ISOs are available from https://downloads.freepbxdistro.org/ISO/

...

Please refer to below wiki page about installing 16.0 on Debian platform. 

https://wikisangomakb.freepbx.orgatlassian.net/wiki/spaces/FP/pages/viewpage.action?spaceKey=FOP&title=/10289322/Installing+FreePBX+16+on+Debian+10.9 .

Or use the URL below to download the latest FreePBX 16.0 release tarball. 

http://mirror.freepbx.org/modules/packages/freepbx/7.4/freepbx-16.0-latest.tgz

Frequently Asked Questions:

...

A:  Yes. You are free to deactivate your deployment ID from your existing system and activate the same deployment id to your new FreePBX 16.0 system and expect to get the same supported licenses. Please refer to https://wiki.freepbx.org/display/FPAS/How + to + Move + a + PBX + Deployment + to + a + New + PBX to learn how to move your deployment to another PBX.

...