I added a bunch of the fake browser IDs to the list of bots, hoping among these there isn't one of a real browser (well, some are, but old outdated versions, most likely).
But even with that, these are so aggressive that I don't know if the site can work without the bot filter when they are scraping it. Maybe for some like that I should add a permanent filter then, I'll try to do that in the next days. Hoping that they don't start using real current browser IDs (instead of some that are just similar).

If someone gets blocked because identified as a bot, please open https://ksle1.antp.be/user-agent.php and give the ID that is returned for your browser.

500 Internal Server Error on the main site . Happened twice today ( don't remember the time for the 1st one , 8:54 PM ( Baube's time ) for the second one

I've enabled the bot block a couple times already today

It is heavy loaded, some requests work some don't. A site on a single server like here is not made for thousands of bot requests per second
Maybe I should at some point consider using Cloudflare services.

Enabling the bot filter may help a little, but since some of these new bots are not filtered by it, it won't solve all issues.

I had same as Walter above for a few minutes about that time - frozen blank screen with "500 Internal Server Error"

Now it's happening again ....

500 internal server error.

Guess we are still down.

Either we had tens of thousands of extra visitors, or there are some new bots using random IPs and browser-like user agent, so very difficult to filter out...

There is a gap between 13:00 and 13:40 in the comments, I suppose there was an issue at some point between these times. I'll see if I find something in the logs.

Seems that the site is down right now.

There is a new agressive bot from Singapore, which does not have a specific name (so I'm not sure what it is), that identifies more or less like a web browser but fortunately it uses version numbers that seem rather unique to bots, avoiding to block real users (I hope).

It was added to the bots list, so when the bot filter is enabled that one is blocked too (and the rest of the time it is slowed down like other bots).

It was also the culprit of the issues that sometimes occurred on the image server (comment pictures), as it was browsing too aggressively the forum of my site. It is now banned from there, hoping its identified won't change to go around that.

They use various IP for their requests, so if I want to block it by IP I would have to block a whole range of Singaporean IPs.