PlantUML is XXX days old

[bartoszski]

hi
i am trying to run your example but have :

'''
PlantUML 1.2021.15
This version of PlantUML is 462 days old, so you should
consider upgrading from https://plantuml.com/download
[From string (line 6) ]
@startuml
title Internet Banking System - System Context
top to bottom direction
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4.puml
Cannot open URL
'''
thank you
Bartosz