Updated articles are not included in newsleter

I update weekly the same post (list of meetings – times and places).
I’d like to include it each time in the weekly newsletter, but it seems that only ‘post_date’ is used to query posts, not ‘post_modified’.

Is there a workaround ?
I don’t want to duplicate the post each time.

thx

https://wordpress.org/plugins/wysija-newsletters/