Addon SDK v2; Better video support; Prompt on close & lots more.
I already hate Custom Addons since i realized how stupid they are. Not in a good way, i mean they are really useful sometimes only when the developer itself care about for a brief moment or really need money from their plugin sales. until then they disappear and left the plugin unmaintained.
My suggestion, use built-in feature construct has. it is very powerful enough to create online databases, purchases, and even custom patch and online updates.