OK behzad, I am not quite yet in the same position but I have v17 and v18 installed and I have very few remaining days to await the end of my Update Service. Rah!
Which reminds me, I better check the rubbish in my Xara Online account as it will disappear sometime this year.

I assume you too have v17 nagging you as Magix is being really kind to let you know you might be missing out. This is better than never being told as some Customers were never advised of major version jumps in the past.

Here is how I would block the nag.
You cannot right-click it directly to see its Properties but it has a Taskbar presence so right-click on its icon.
My current nag states it is Updater.
Right-click that and then pick Properties.

The Properties dialog declares this is Service_rel_u_x64_vc12.exe running from C:\Program Files\Xara\Xara Designer Pro X\17\UPS\.
All I do is change the UPS folder to UPSXXX and no nag.

Magix also have its Download Manager hiding in an Online folder; I OnlineXXX that folder as well.

Clearly you can be more surgical but Magix deserves a sledgehammer action.

Acorn