Sorry Alexandre, English is not my first language and maybe I can't translate my ideas into words.
I think Tim's problem is with Raspberry and is not related with this problem (that's what Jason and Greg said).
I understand that you are angry, but I don't see how you expect Xojo to help you. Your host provider said: Our VPS platform runs on specially-modified 2.6 Linux kernel, do you really think that when Xojo put the requirement to run the software do they mean that any 'specially-modified' installations should also work? Will you be less angry if Paul add a note saying that if the Linux installation is modified in any special way the web apps may not run? Do you expect Xojo to buy hosting with your provider and expend X amount of time just to fix this for you?
Don't get me wrong, I'm not defending Xojo, 2018 version is far from perfect, what I'm trying to say, if I were you I'll try to give Xojo more information/tools and even access to the VPS (a new installation for them to try).
If you can't help them try in your environment and they don't have access to it, they won't be able to see if they can change something in their end to make the web apps work.
I don't know if Xojo 2018 is having problems with the 'specially-modified kernel' only, or other things that your VPS changed, so I think is vital that Xojo Inc can test with your VPS, they do have the option to say that they don't support modified installations.
Really I'm sorry, I do hope that a later version of Xojo will work with your host provider, but what is happening now is that the latest release at this point doesn't work.