Well we asked and looks like Beachhead listened , starting the next Clan War , Clan rosters will be locked the day before a clan war starts .
you will still be able to add new members to your clan but their scores will not be counted towards your wins.
*source Beachhead dev on Reddit Clan wars: roster lock is coming! : CODGhosts
They haven't posted about it yet! Follow @beachheadstudio and @CallofDuty for clan war news!
THANK YOU! finally!, i hope this is true! now it will be a real clan war, and not just a war to see who adds more people the fastest to win! good news!