I’m an avast user and not an avast employee, so I can’t speak for them.
However, support for avast 4.8 is due to cease at the end of this year. Avast 6 has been out for over a year and there are also avast 6 business solutions (win9.x and winME OSes are no longer supported from avast6 or higher). Avast7 has also been released earlier this year, but the business management software is still on avast6 versions.
So you best option would be to contact sales (at) avast (dot) com as they will have full information on the product availability and what would be best to meet your requirements.