Force password update on first login

add_filter( 'wpmem_login_redirect', 'password_change_login_redirect', 10, 2 );
function password_change_login_redirect( $redirect_to, $user_id ) {

    // Check for the presence of a flag if the user has logged in before.
    $first_login = wpmem_get_user_meta( $user_id, 'first_login' );

    // If the user has never logged in, do this:
    if ( ! $first_login ) {

        // Set that the user has logged in the first time.
        update_user_meta( $user_id, 'first_login', 'true' );

        // Return the user profile url for password change.
        return wpmem_profile_url( 'pwdchange' );
    }

    return $redirect_to;
}