Tom B
The eZine PDF format was convenient for printing and later reading. I hope Cakewalk will provide something similar soon.
Actually Cakewalk didn't like the PDF format because they felt something like a Word doc would be more searchable and give better SEO. Of course Google can find things in a PDF; for example you can search on "Anatomy of a SONAR Project" and all the eZines that had that feature appear, however serach won't take you to the article itself within a PDF. (OTOH I felt that was an advantage because it would make people aware of the eZine

.) I also felt the PDF format was more convenient for users because you could, for example, load it in an iPad along with your other manuals and documentation or print it out (I keep all my manuals in an old iPad, it makes a great "library").
But another reason for discontinuing the eZine was because when I started doing it, I was providing a lot of content for the updates like FX Chains (VoxTools, Monitorizer, Sizzle Bus, etc.), amp sims and pedalboards, loops, etc. Instructions for how to use them was not included in the release notes, so the only way to describe applications was through the eZine. However Cakewalk feels that users weren't that interested in the content I did, so as you may have noticed there hasn't been any new content in over a year - but to Cakewalk's point, I don't think they've received any "Hey what happened to the content" emails. This meant that a main reason for starting the eZine was no longer relevant. (I do hope to do something like set up Dropbox to make the content Cakewalk never used available, I have a lot of stuff sitting on the shelf and I think at least some people would find it useful.)
Meanwhile there are the release notes to cover the various new features each month...when you open SONAR, just go
Help > What's New and you'll be up to speed on the new features.