I did this and it seems to be working:
- Formatted and installed Server 2008 R2.
- Changed the date to 2019.
- Restarted and re-formatted and re-installed Server 2008 R2, so that the first date that the OS will see, is 2019.
- Start-> Administrative Tools-> Services
- Double click on Software Protection service.
- Changed Startup Type to: Disabled.
- Restarted and changed the date to 2009.
- Everything seems to be working fine, windows update works.
- Changed the date to 2018.
- Everything seems to be working fine. No watermark about a non-genuine version, does not ask me for activation. So, i just changed back the date to 2009.
I think this is the solution.