If you were to leave jessie-backports open that may save you some downgrading.
I agree a fresh installation is best, maybe side by side and copy your .conf files over, but to me it is worth the experimentation and reporting that it can safely be done, today, with current state of the distributions (ascii --> jessie).  A month from now it will not be a good indicator that it can be done.

What about things that exist on ascii and don't exist in jessie?  Would they be retained as local installations or dumped?  I assume the first, but what if their dependencies don't match or are inadequate?  Thinking of OpenRC, eudev, runit, sysv-rc, etc.

Those are all valid jessie repositories, pick and choose.  Some may not have a contrib and non-free components.

deb https://pkgmaster.devuan.org/merged/ jessie main contrib non-free
deb https://pkgmaster.devuan.org/merged/ jessie-backports main contrib non-free
deb https://pkgmaster.devuan.org/devuan/ jessie-proposed main contrib non-free
deb https://pkgmaster.devuan.org/devuan/ jessie-proposed-backports main contrib non-free
deb https://pkgmaster.devuan.org/devuan/ jessie-proposed-security main contrib non-free
deb https://pkgmaster.devuan.org/merged/ jessie-proposed-updates main contrib non-free
deb https://pkgmaster.devuan.org/merged/ jessie-security main contrib non-free
deb https://pkgmaster.devuan.org/merged/ jessie-updates main contrib non-free

https://sysdfree.wordpress.com/151

Here is some reading material

You should look up the three debian security alerts

https://meltdownattack.com/
https://spectreattack.com/
https://meltdownattack.com/meltdown.pdf
https://spectreattack.com/spectre.pdf

https://security-tracker.debian.org/tra … -2017-5715
https://security-tracker.debian.org/tra … -2017-5753
https://security-tracker.debian.org/tra … -2017-5754

https://xenbits.xen.org/xsa/advisory-254.html
https://googleprojectzero.blogspot.co.u … -side.html
http://blog.cyberus-technology.de/posts … tdown.html
https://01.org/security/advisories/intel-oss-10003

No crash yet!
   I  dragged and dropped links from the bar to a webmail draft, from a link on a page back to the bar and from bookmards to bar and page and not a single problem.  And that is with a gazillion of tabs open.
Maybe some addon is causing it.  Mozilla goes out of its way to invalidate addons from other providers.  Noscript and most other mozilla plugins that work on ESR work on Palemoon because the backbone of palemoon is built on old mozilla code and incorporates only the "sane" updates. Noscript works on ESR and palemoon just the same, while on 57 it is an annoying gadget.
The bad thing about ESR is that eventually it will become like 57, as it was less than a year ago that it was based on 45.  Enjoy it while it lasts.

The reason i searched for other solutions was that I couldn't trust mozilla any more than I trust google, yahoo, msn, etc..  Which is ZERO!
Privacy badger is EFF which is a Mozilla non-profit publicity scum.  https://www.eff.org/deeplinks/2016/04/save-firefox

Each distribution in Debian/Devuan has a filesystem chart and it is different from each other (we touched on this topic on the other conversation about ascii).  Dist-upgrade brings what the distribution prescribes of pkgs while apt upgrade just searches the repository you point it to, for newer versions of the pkgs already installed.

Somehow Debian managed to even trip its own packaging tools so even a plain apt upgrade from wheezy to Debian jessie would require systemd stuff to come in (as dependencies of depended pkgs.  Apt upgrade from wheezy to Devuan jessie (or ascii) produces a fine system.  But since you will be shifting to devuan you may as well apt-get dist-upgrade for the full experience

On synaptic the difference is called default upgrade vs smart upgrade, smart being dist-upgrade.  (check on the preferences 1st page).

There are people who will disagree on this as apt and apt-get had different structures in the past but things have changed.  apt-get upgrade and apt upgrade are the same thing.  There is no such thing as apt dist-upgrade.

I hope this helps, and I welcome corrections on this view based on evidence.
I still have a functioning installation, I think my very 1st devuan, that is basically ascii converted from Devuan 1.0.0.0.  that I had exposed to debian/sid, did an apt upgrade to see the list of upgradeable pkgs, took off the list the ones I expected to be problematic, and upgraded a ton of things.  I haven't done it again for a few months now, but it works fine   I call it frankensidevuan!  Maybe I should call it GMO-linux

Hmmm,...  time to give that installation a transfusion of some fresh sid blood.

My kind of person, but what ends are those two?
I have 2 arch based non-systemd distros on that other end (Debian and Arch basis being 95% of linux) the one is Artix, and the other is Obarun.  I'm even testing 4.15-rc* at the moment as 4.14s have been stable for a while now.
Except for the ready made Arch based linux-kernels there is a ton of stuff on AUR you can custom compile for superfast kernel built for your specific hardware.  It may take a day of processing with an old machine but it is worth it.

I have gotten 4.15rc from Debian experimental and it works, only it does some funky thing with processor speed which I need to study up on.  It seems it keeps the processors at low speed till there is a demand for them to do hard work.  It is like an old GM trick of running V8s with a couple of cylinders dead till there is a need for power.  Horrible idea on an engine.

I don't use it that much, but have used it as that new crappy ff 57 was a disaster.
It never crashed on me but I don't really drag and drop addresses either.  I like copy paste better.  Right now I am on a system that only has Palemoon which is my preferred browser for some time now.  I will try drag and drop tomorrow on the 52 and report back.  I just saw the past 48hrs there was an update of 52 but it may be on Deb-sid.  Maybe get it from there if it is not ceres, it may have a fix.

I haven't gotten palemoon to crash once for months, it works on all videos, and it is like ff-esr use to be.  I hope it stays this good!  A new installer just came out for it too, 0.24, and it works like a charm.  Keep the installer handy and check for updates.  I have used the same installer in about 5 different linux systems.  2 thumbs up!

FFesr takes about twice the Ram to do the same stuff with PM.

On my old (since stone age) Debian installation I have about the same ob setup.
When it starts up the static RAM is about 2.5 times more than it is with RedrasciiOpenRC.
About the only thing that can beat this is Obarun without a DM.  It is also the fastest booting system I have seen.  S6 has yet to produce a single freeze or crash of any form.

Sorry for the above I took a look and seems the whole X in Jessie is of a much older edition than that of ascii.  So I don't think a partial installation would be compatible as it also replaces a couple of X11 server pkgs. 

If you can compare lspci -k from both kernels you may be able to find what is missing or different on 4.9

Also, if you really want to get deep into it and have the time try the ascii iso from refracta to see if it works.

Everytime I see nvidia in a linux forum is like looking at a can of worms.,

Hey did you hear about the funniest joke in human history?

it even made golinux crank a smile