Hello! Servers are generally eligible for Cross-server events after hitting the 60 days in age of server. This time frame is not completely accurate as the process to add servers to cross-server events requires a maintenance. There are times when servers are not added to cross-server even after the 60 days mark. When this happens, it should be reported here.

If you are asking about the "next server" that would start Cross-server events, there is no definitive time as there is a general time frame when servers are added.

If you wish to know the general time frames for servers, you can find out when servers opened here in the News Section and count towards the 60 days mark. This will allow you to find the approximate time when a server could possibly get Cross-server events.