TLDR; If upgrading to Zabbix 8.0.0rc1 causes your Zabbix UI to completely die to “Component router is not registered” message, try disabling 3rd party modules.
Zabbix 8.0.0rc1 is out! My What's up, home? Zabbix had been running on 8.0.0beta2 successfully, but during 8.0.0rc1 upgrade it was a close call that this would have been one of those flights where a plane lands but passengers take off. Luckily, the solution was simple. Huge thanks for one of the Zabbix support engineers for pointing me out to correct direction.
What happened?
During upgrade, all went well – database migration went through fast, Zabbix server started up and started working, Zabbix Agent 2 restarted just fine. But when I tried to hop on to Zabbix web GUI, oops,
- GUI only said “Component router is not registered”.
- nginx error logs did show various stack traces from php-fpm.
As I kept my old config files when apt offered to replace the config files with the ones coming from the repository, at first I thought that the new web config file would contain something that I'm now missing and causing the havoc.
No, it was not that.
Root cause
As 8.0rc1 came with a big bunch of new features, underneath code had changed in such ways that outdated 3rd party modules caused Zabbix UI to break. In my case, I had
- InitMAX uxMAX module causing the total meltdown of the GUI, but I admit the module version I had in use was very old.
- monZphere's WorkflowOps module caused other, yet irritating UI bug; graph tooltips opened to top left corner near Zabbix logo, plus rendered a static “Array” word to that area too.
After disabling both modules, Zabbix started to work as usual.
Back to good stuff
Visual refresh
Zabbix 8.0.0rc1 comes with a new dark blue theme, which easy on the eyes to read, but not so harsh or boring like some black or dark grey dark mode. There's a bunch of other tweaks too but not gonna list them here now. 
APM
Finally Zabbix has APM with traces, metrics and logs. I have yet to test them, but hey, the connection to my Raspberry Pi 5's Clickhouse installation already works!

For using APM, you need to install a Zabbix proxy too for any data collections. While I'm typing this, I'm trying out if my Omarchy Linux laptop installs and configures one for me. After that, I get to install some actual data collection.
But look at this. FINALLY!

EDIT few hours after publishing the original version of this post: YAY I'm now successfully tracing my home Grafana with Zabbix. :D
Complex Event Processing
It's finally here! By the looks of it, it will take bit of reading and learning to actually get the most out of it, but just by looking at these examples that ship with Zabbix 8.0.0rc1, it's easy to see that there's a lot we can do with CEP. More on that later, and I cannot wait to hear about this in about a week in Zabbix Summit 2026.
My Omarchy looks like it's done, so off the proxy & APM testing I go. See you at the Zabbix Summit 2026 soon!