mIRC needs a change in the servers list storage and distribution implementation.
mIRC should do the following:
Default servers should be stored in the file: servers_default.ini
User defined servers should be stored in the file: servers.ini
The UI for browsing servers should include a drop-combo: "All Servers / Default Servers / User-defined Servers"
Migrating to this new paradigm, mIRC will come with a new "servers_default.ini" file and mIRC will delete all exact duplicates from "servers.ini" leaving behind only the user-modified servers and the historic-deprecated servers from a bygone era.
Now when mIRC is installed, new servers can always accompany it without destroying the user-defined servers.
The drop-combo selection of "All Servers / Default Servers / User-defined Servers" will specify how mIRC behaves when connecting to and rotating between servers.
* If "All Servers" as last selected, mIRC will prioritize connecting to User-defined servers first, and failing that, will move onto servers in the Default Servers list within the matching group name.
* If "Default Servers" was last selected, then only servers within the Default Servers list will be rotated through when connecting to any groups within this list. (If said group ONLY exists within the User-defined Servers list, then it will still attempt to use one of those servers.)
* If "User-defined Servers" was last selected, then only servers within the User-defined Servers list will be rotated through when connecting to any groups within this list. (If said group ONLY exists within the Default Servers list, then it will still attempt to use one of those servers.)
Servers will be considered as a "Duplicate" and "overridden" if they share the same exact "Server Description" name between both files.
This behavior will enable updates to mIRC to allow new servers to be introduced to and removed from an existing Server Group, with user-expectant behavior and security in mind. User-defined definitions being preserved and prioritized, and, used exclusively so configured.
An augmentation to the drop-combo suggestion above, it could instead use an "[x] Include Default Servers" checkbox instead if you think this would make more sense to users.