BillManager 4 versions difference

BILLmanager has some versions to install
BILLmanager Standard - the easiest version which can fully solve the billing tasks for small company.
There are the following restriction for this version:

- Only one hosting project can be supported. - Only one command is supported to get payments and one payer from each customer. - Only one datacenter is supported which has the accounts. - The set of proposed services is restricted: Virtual (shared) hosting, Virtual Dedicated Servers (VDS/VPS), domain registration. - No partner programs for clients. - Client can have only one login to log in the billing system.

If you need to update the current billing version to Advanced or Corporate, you can pay the price difference and have the advanced features without system reinstallation. 

BILLmanager Advanced - all restrictions of Standard version are removed, except using only one hosting project. If your company have some trademarks or separate projects, you should buy Corporate billing version
BILLmanager Corporate - the fullest billing version with no restrictions.
BILLmanager RU-CENTER - free billing version for partners of nic.ru domain registrar where one can register the domains from Rucenter.