Timo, I already noted you in the private message,even when you had 1.6.,  that this bug is caused by some third-party plugin and you have a lot of them, you will need to disable them one by one to see which one causes that and you refused to do that. 

Ross i have to say this issue has been seen on my site and before the update I did not have this issue. I even removed all third party plugins and finally just uninstalled the plugin because it was lagging my site pretty bad

I have the same problem, Messages plugin completely slowed down my website.

yes same here I even tried changing teh settings for larger sites and still lagged real bad 

but instead of the Oxwall staff saying ok we will check into it they say oh we have been through this with you before its a third party plugin I learned long ago you may have been through situations a million times when it comes to an oxwall update you should listen to the users they would re-report something unless they were basing it on something solid

Jozef, what hosting plan or server do you have?

VPS:

RAM 2GB, 

HDD 100GB, 

VCPU 4

(5 active users)

Jozef, can you please provide us with the Cpanel and admin access details so we could check the CPU issue on your website?

Guys, mailbox plugin has been updated, please update it. The notification should appear in your admin panel within next 24 hours.