Question What is procedure to decommision Plesk, but keep server running?

[mr-wolf]

I have a Xen DRBD virtual server with an unlimited license running at a provider.
The server is old, running Plesk 12.5.3 on CentOS 5.11, but is running our authorative DNS, 2 websites and 2 mail accounts.
I have migrated all but these 2 websites away and want to replace it using a fresh installed Ubuntu 16.04 LTS with Plesk 17.5.3 on which I want to use the license I'm having on that old server.

Somehow I'm unable to get those 2 websites running on other servers using the migration tool. I can remember having problems with those same sites when I migrated them from another provider to us. I did it manually then. I haven't tried that thus far.
Both sites are extremely out of date.

As I want to have Plesk 17.5.3 on a fresh new VPS with a high SLA running my authorative DNS I'm thinking of decommisioning Plesk on the old server and make it an affordable VPS (as well stripping its high SLA) so I can keep running those few accounts without putting much effort in migrating those domains.
Its license I want to use for the new server.

Can I just give a command to remove Plesk and trust that it is not touching any of the settings of Nginx, Apache, Courier and Postfix?
Please elaborate on license issues as I don't want to do anything to violate the license agreement.

I have several servers at Strato, but this server is somewhere else and has a full license directly from Plesk.

 

[IgorG]

Can I just give a command to remove Plesk and trust that it is not touching any of the settings of Nginx, Apache, Courier and Postfix?

I would not advise doing this. The consequences are unpredictable.
Regarding licenses I would suggest you install trial license on your new server and migrate all that you need from old server with full license. After that you may install your full license on this new server. You can ask assistance regarding license questions here - Licensing and Purchase support - Plesk