First most of these messages should only show for Admin users and not all users.  You can turn off the blog posts by going to the settings page and select Orion Product Blog link and un-check "store blog posts" and save.  You can also disable product update notifications as well by going on the same settings page the Product Updates section and un-selecting "Enable Product Update Notification" and saving.

Doesn't work in NCM. I unchecked the boxes as mentioned above. I hit refresh and it's right back. I tried in 3 browsers on multiple machines. No difference.

9 new blog post(s) » More Details  Dismiss Message

BTW, the X to the far right is purely decorative, it does nothing when clicked. BTW, look at the Last Check date below ...

Where are these settings in 2019.2?