You don't give us much information to go on, but it seems as though you must be renting a server from a host that uses multicraft, in which case you almost certainly can't install your own phars, only choose from the list they provide. If the PocketMine dev phar that they propose in that dropdown list says "outdated" then you need to ask your host to provide a more recent version.
You can upload them, but from the screenshots you posted you probably can't install them - by 'install' I mean upload the .phar and .phar.conf files to the correct JAR directory so it shows up in the dropdown list
What about console users? If its a network, you'd really need few consoles. If individual, you'd need an owner with you or helper at least.
I think at the moment he's renting a prebuilt 'plan' for which the host uses Multicraft, not actually setting up his own PM installation. There's no point at all using multicraft for a single PM server on a machine where you have root access, unless you need multiple staff accounts with console access, and are prepared to pay to remove the 10 user multicraft limit.
I hope you're not paying them more than $5 to host your server. Anyways, Settings -> Update Minecraft -> Add or Remove Files. That's where you change the core.
You could add it on your Daemon DIR instead of that crappy "settings" section. I'm sure that if they buy a prebuilt plan Server they will not provide with SuperUser console level.
ok so i just did what you guys recomended to the original thread maker. deleted my server and reinstalled a new one clean with the newest phar using this command also before i clean reinstalled it i also tried replacing the phar with the newest one and got the same error Code: curl -sL get.pmmp.io | bash -s - -t poggit.pmmp.io/get.pmmp -v custom i save my old world and plugins before hand) and i get an error and it wont run [update I am not fit to be part of the human race I should die. XD the error was because another server was already running on that port I am so stupid sometimes. actually all the time...]
not necessarily. that error just means that the raklib thread had much fun (irony). In most cases it means it couldn't bind to the port, but it does not necessarily need to mean that.