How to set up a Weekly Digest I need to set up a weekly email digest of all content from a few particular content types (latest news, latest tech articles etc.) for all users in a particular group. 

I have Simplenews installed and it looks like the Simplenews Digest module is not updated. Is there anything else that offers the feature I am looking for?
You can make an RSS feed of the digest and then use Mailchimp to make a newsletter of that RSS feed.
This has to be setup one time and the rest is automated.
Mailchimp module synchronizes Drupal user groups with the mailing lists and groups.