In the aiscript for each waypoint, there are blocks of script called action tests. They look similar to this:
Code:
action 0 //east tower door
{
node_connect 3 129 true
node_connect 129 23 true
}
these are executed when an event occurs on the corresponding entity for the action (like a wall being destroyed). Originally, a script could only have 16 of these. Since some larger and more complex maps have been waypointed (and new ways to abuse ETPro map scripting were discovered) it became necessary to have more than 16 action tests. It's a "beta" release, but nothing in there should affect stability of a server.