APT INSTALLER UNIQUEMENT MISE À JOUR

#For example if apache2 package is already installed, it will try 
#to update to the latest version. If you do not want to install 
#new packages; when used in conjunction with install, only-upgrade
#will install upgrades for already installed packages only and ignore
#requests to install new packages. 

sudo apt --only-upgrade install apache2
Panicky Pintail