Some premium functions are still in AMS 5 (which is free), while others are not.
e.g. the firewall is currently not there anymore, but will be back in a future version.
I haven't seen a complete list with the options in AMS 5 though
As I understand the license will be stopped meaning the premium features you have in AMS 4 will stop functioning if they are not in AMS 5.
For the time your subscription is/was still valid, avast will give you SecureLine.