This is the class upgrade_navigation
| package | 
                                                                                    
                                                                                 Installation  | 
                                
|---|
checkVersion(object $version) : boolean
object
                                            boolean
                                                                    description() : string
string
                                                                    name() : string
string
                                                                    needed() : boolean
..)
boolean
                                                                    prioritize( $a, $b) : boolean
                                            
                                            boolean
                                                                    upgrade() : string
string
                                                                    from_version :
                                                                            to_version :
                                                                            optional :
                                                                            priority :