What happened:
Last week, just three days before the lottery, the disk space of our VPS server went to 100% over night causing the website to fail to load. Unfortunatelly i only saw the warning email 2 days later (had a busy weekend) and by the time i managed to get help from the hosting company, KO was already down for three days.
The problem was fixed and everything seemed to be back to normal until yesterday when again, both the disk space and the cpu went at 100% causing another crash which lasted ~12 hours before getting fixed.
Apparently these crashes were fueled by the old PHP (the programming language our website and our forums are built with) version but i upgraded it meanwhile to a more stable version.

Unfortunatelly, the forum software doesn't support the latest php versions (7.2 an 7.3) so i had to stick to 7.1 (which is still better and much faster than what we've previously had - 5.6).

Even with 7.1, there were still some incompatibilities with the forums so i've upgraded the software to the latest stable version i have licence for (4.2.5), i disabled some plugins and now, hopefully, everything should be nice and smooth again.

What does this mean:
The speed should have visibly increased by now in both the homepage and the forums. (7.1 is twice as fast as 5.6)
Normally we should not experience any more crashes.
There might still be small errors and bugs, if you see anything that doesn't look right please report it here.
I'm thinking about getting a licence for vBulletin 5 or even switch to ZenForo (a beautifull forum software) because else we will not be able to upgrade to newer and faster php versions but this is on the long run.

Bottom line:
Sorry for the recent downtimes, i really hope we're not gonna go through anything like this ever again, it was a pain figuring out what went wrong and have everything fixed.