I use phplist3 to send an external web page to my list weekly. In the mail subject every week should be the calendar week and the year, for which basically [TODAY:W]/[TODAY:Y] works.
I already know these links:
However, it seems to me that the mail subject always contains the same string as when it was first sent. [TODAY:W]/[TODAY:Y] correctly becomes 40/2022 the first time, but after the first time it stays that way every time it is sent, so it doesn’t update.
@Mr.M If you are using the date placeholder plugin then there is a configuration setting to fix the date when the campaign has been sent. You probably want that setting to be No, so that the placeholder remains in the subject field.