You can download PRO (Pokémon Revolution Online) from one of the download links below.
You will need a file-archiving extractor in order to open it; WinRar is the most recommendable one for PRO. Once you have downloaded it, extract all of its contents into a new folder.
All download links itemized here are reputable; therefore, if your anti-virus program(s) and/or Firewall are flagging it as harmful, you can consider it a false positive. Try another one of the mirrors if that is the case, or add the program as an exception to your Firewall and/or anti-virus program.
Whenever a new client update occurs, you will need to redownload the client to have the most up-to-date components. Check the revisory log of this page to ascertain how up-to-date these versions are.
Current version's namespace: PRO Lugia.