summary/notify-feature for elgg?

hi there. 

please excuse me if this question was asked before or is silly – i'm new to elgg and of course
i did a research through the community and the plugin repository before. 

i'm searching for a solution to notify all users (via e-mail) when there are updates on the site. 
it's an medical support group with rare updates and older and »lazy« users. a kind of weekly summary
like »discourse« is offering, would do the job too. 

i know the »content subscription« plugin and its nice, but it's working for discussions (and manual 
subscription) only. do you have any idea to solve it? 

thanks a lot!