I need to install this major release and I want to know how I can do it.
I proceed with the normal upgrade procedure on this link(https://community.dynatrace.com/community/display/... or there is an other mode?
You say you want to upgrade from 12.4.2 to 12.4.11.
you linked to should do the job under normal circumstances.
Be sure to read
and, if you have a farm deployment, be sure to read
I don't understand, I must upgrade all (CSS, RUMConsole..) to the same version(12.4.11) or I can also upgrade only the CAS?
Because I've a ticket opened with the support and told me that upgrade the CAS to 12.4.11 could solve a problem that we have.
it is a top down approach, CSS should have the highest version, RUM Console the same or lower, CAS the same or lower than RUM Console and so on.
It might be possible to install the servicepack (12.4.11) only on the CAS, you can ask your support contact in your ticket for this. But it will be better to upgrade CSS and RUM Console as well. These two components can be updated very quickly.