I taught in a similar school. We put all our info on line. I'm saddened that no one read the on line website. One thing we had a problem with was parents thinking that, because they paid tuition, they could have instant access at any time to any teacher for personal info/updates on their children. No two parents got the same info that way. It was inefficient.
Our local public schools have something called "The Virtual Backpack" where they are instructed to check for assignments, events, schedules, field trips, etc. The sign in front of the school often has timely messages too, with frequent reminders to check the VB - it puts the responsibility in the parents' laps and prevents them from saying they didn't know what was going on.
No way I would do a paper newsletter - it's inefficient unless you have a family without internet access. Besides, kids don't deliver them, parents find them months later in the bottom of the backpack covered in old juice stains and cracker crumbs, and long past the date of applicability.
What I did for my middle schoolers was write out my expectations and general curriculum at the start of the year: what book(s) we were using, general topics for the first few months, how I graded (what mix I was using of tests, quizzes, class participation, homework, projects, learning games, small group/team work, etc.), and roughly how much homework they could expect. I told them homework assignments would be posted on the website. I explained my philosophy of teaching and learning. I indicated my position on make-up work, extensions and test re-takes - I let kids re-take one test per term, and I gave other opportunities for ameliorating the effect of one bad grade on the total term grade, plus things I offered for extra credit. I listed supplies that were needed and volunteer opportunities, as well as a "parents can help their child by….."
Thereafter, I gave updates - "We're working on XYZ, students are writing a series of skits/plays to put on for the younger grades, and we're taking a field trip to ABC or having a class visitor on Topic D." I gave reminders about due dates for big stuff (projects) and listed topics to be reviewed/studied for an upcoming exam.
If I had concerns, those went in an individual email. If I had something awesome to report, that went in an email. Emails included in the "signature" part a reminder to check the website.
There was a school newsletter, and I always made sure I had timely articles in there about what we were doing. That was a good place for the "fun stuff" like how the little kids reacted to the assembly where the middle schoolers performed classic kid stories in Spanish or set something to music.
Honestly, if parents can't be bothered to check the website (assuming it is well publicized and easy to navigate), I don't think you have to substitute individual emails (people don't read those either) or paper updates. Emails should be for their own child's information, or reminders for things like permission slips (send to all those affected but keep the recipient list hidden so Parent A doesn't know that Parents B and C also didn't complete the slips).
Don't make more work for yourself just because people don't use the system.
And I don't think middle school parents need - or should have - daily updates. Kids are supposed to be learning to be more responsible by that age, and I think those are essential skills and expectations to be teaching. Parents may be very involved (regardless of socio-economic status) but they need to make their kids more responsible as a life skill in preparation for high school and college and jobs.