About: Lan

Thank you Cristian. I’ve read the thread you recommended, but it seems to be different from what I hope to do? as it sync with mailchimp during the registration.

I hope to understand is whether we can update mailchimp merge tags for “existing WP users” (not newly register ones) with my customized WP database fields.
which filter should I use?
add_filter(“ws_plugin__s2member_mailchimp_merge_array”, “my_filter”);
or
add_filter(“ws_plugin__s2member_mailchimp_update_existing”, “__return_true”

thanks for your help in advance

Oops, I put in that hook, however got an error message saying

Warning: Cannot modify header information – headers already sent by …/s2-hacks.php:2) in ../wp-login.php on line 349

How can I fix that error?
Thank you for your advice