To protect against piracy, we have license checking on per IP basis. Although you are allowed to use the license key on all servers you own, this means that you will have to get each IP you want to use whitelisted. To get a license key whitelisted, you will have to contact the developer (e.g. via email). The first server you use your plugins on gets automatically whitelisted.
Due recent changes introduced by Unturned to Linux builds, we can not guarantee support for Linux servers anymore. Our products only support Unturned builds with .NET 4.6 (which is only guaranteed on Windows and Mac at the moment). SDG has promised to add separate .NET 3.5 and .NET 4.6 builds for Linux, so be sure to install one supporting .NET 4.6. It is recommended to use a hoster which provides Windows-based servers.
ImperialPlugins does not have any social media accounts (e.g. VK, Facebook, Google Plus, twitter). If you find any account selling plugins that claims to represent ImperialPlugins, they are very likely trying to scam you. Keep in mind that some developers have social media accounts and sometimes sell their plugins there too.