How can I change the format for all dates through the entire forum into j F Y in stead of the format used by bbPress?

Which files do I have to change?

[@netweb Keymaster 11 years, 1 month ago]

Change your WordPress settings (/wp-admin/options-general.php) to whatever format you require, bbPress will inherit those settings.

[@vincebalk Participant 11 years, 1 month ago]

Well, unfortunately it does not. I use multisite, does that matter?

Settings are j F Y and H:i

Lang is nl_NL / dutch;flemisch

[@netweb Keymaster 11 years, 1 month ago]

Can you try this instead 😉

Either add this to your themes functions.php or your bbpress-functions.php or download the entire file and install it as a plugin from https://gist.github.com/ntwb/7767761

add_filter ( 'bbp_get_reply_post_date', ntwb_bbpress_enable_date_translation, 10, 6);
add_filter ( 'bbp_get_topic_post_date', ntwb_bbpress_enable_date_translation, 10, 6);
 
function ntwb_bbpress_enable_date_translation( $result, $reply_id, $humanize, $gmt, $date, $time ) {
 
	$date = get_post_time( get_option( 'date_format' ), $gmt, $reply_id, $translate = true );
	$result = sprintf( _x( '%1$s at %2$s', 'date at time', 'bbpress' ), $date, $time );
	return $result;
}