Just thinking out loud...
 
1) Capsulize your previous CW work.  Get an export method down-pat. (I have DOS stuff, so lots of work to do)
2) Find your new DAW.  (Seem's like Studio 1 v3 is a fav for Win & Mac).
3) Take your butter Plugins (I have a love grip on Z3TA & Dim, and anything Anderton did,<thks Craig>)
4) Learn what you new DAW like in the was of work flow
5) Figure out where we are all going to meet-up?
 
This is a crude start, perhaps i'll start a twitter account/tag #byebyeSonar
There must be a best practices about change management on, let's call it enterprise software
 
I'd would love to be a fly on the wall in the decision to kill SONAR.  Really want to know what's happened...  Was there a critical flaw, too much to overcome?  Did a key player up and quit? Did they try to reach out to Greg Hendershott (the creator of Twelve Tone, now Cakewalk...  Thinking of a Steve Jobs come back!)
 
How about a kick starter to buy Sonar?  There are 141K people who read the demise Cakewalk post.  141k x  $20 =2.8 Mil! I think that should pull anybody out of the hole.
 
Maybe too many thoughts in one post.
 
There's a hold in my life!
 
bRAD
 
 

sadly, sonar is dead. i could see burning through 2.8 in a shorter time than it would take to write a DAW from scratch with the best programmers ($$$$), thouroughly qc it, have tech support and marketing in place... i don't see it.
 
i demoed six or seven DAWs and chose cubase. i began a new project when it was down to S1 and CB, the test project just sounded better in CB. if i want to migrate old projects its isn't too tough (see sweetwater article), or i can work on them in sonar as needed...

Cubase Is the only intelligent answer
I have ditched Platinum and just kept the lp  plugins and ZTa from the command centre
No good hanging on to the past

I tried a few daws and nothing made me 100% happy...I bought the crossgrade for studio one and sold it a few weeks later again...
Samplitude seems to be cool...I will keep it for mastering and the independence has very good sounds,but it is very different, too.
Meanwhile I use reaper(60$ is a great prize) as 2nd daw. Sonar will be my main daw as long as possible, but reaper is a fine thing to work with...I can drag the clips directly from the sonar window to the reaper window so it is very easy to work with both. Yesterday I copied a whole project in a few minutes with time changes, fx etc...
 

Sonar is likely to continue to be fully operational on my Windows 7 platform for a year or two, so my migration strategy is a gradual long-term one. I will continue using Sonar Platinum for as long as possible. I will revert to Sonar X3 if Platinum authorization becomes a problem.

Meanwhile, I have already purchased Digital Performer, which in the short term will be my secondary DAW. In the long term it can eventually become my primary DAW if continuing with Sonar becomes imposible. But, right now, as a secondary DAW I did not want something too similar to Sonar, so I chose one that is very dissimilar.

My opinion is . . . if you loved Sonar, you will really like Cubase . . . it mostly does what Sonar did, but the terminology is just different, and it takes a while to adjust to that. You really need to decide what you need from your DAW, so you can move on to the right one. For me, it was important to have excellent midi, and staff view experience.
 
I have programmed all my old Sonar keyboard shortcuts to be the same in Cubase, so the workflow is very much the same. If you use Melodyne a lot, it may not be the best choice, since Cubase has their own (Vari Audio) solution for that, which will take some time adapting to. Remember how you hated Sonar's Audiosnap ? . . . to change the tempo of a project containing pre-recorded audio ? . . . get ready for a pleasant surprise in Cubase.
 
I've now moved many Sonar projects over to Cubase, and I think they sound better . . . I wasn't expecting that, but they just sound better, for whatever reason.

Assuming that Sonar is still working ok, then to hastily ditch it for something untried doesn't seem like a good stategy to me.

LeBassist
2) Find your new DAW.  (Seem's like Studio 1 v3 is a fav for Win & Mac).
 

Having been through all of this and come out the other side with still a bit of sanity left, let me give you some advice. Don't blindly choose a DAW because it's the fav. A lot of people have done that and it seems nuts to me. There are quite a few good DAWs out there and everyone will try to convince you that the one they went for is the best. The best way is to try out as many demos as you can and try to give each demo time before giving up. A lot of people seem to be hungup on Sonar and the Sonar way of doing things. Every DAW you try will have its own unique ways of doing things and it's own quirks etc. So put Sonar out of your head. We all work in different ways so some DAWs are better for some and others are better for others. So find one that works best for you by trying them out.

Sonar may well continue to work for years. But it may not. The problem is predicting when it won’t work any longer. So I asked myself how long it would take to learn a DAW as well as I know Sonar. I’ve been with this program since 1993 and while I’ve dabbled in many other DAWs, I’m not fluent in any bar Sonar. I figure it’s going to take some time. While Sonars development remains at zero is the perfect time to learn a new DAW

So after much examining, trying this and trying that, I’ve gone with Cubase 9.5 Pro. However, rather than wait for Sonar to stop working, I’m just going to stop using it and get stuck into Cubase. In fact this is going to be the first time I have a PC that won’t have a piece of Cakewalk Daw loaded on it.

I’ve placed myself in the same position I was in when the X series came out. Couldn’t get to like it and kept going back to 8.5.3. So I was not really learning the new X series. Solution; force myself to do it by uninstalling 8.5.3. It didn’t take too long to get into the swing of things with the X series once the major distraction of 8.5.3 was gone.

Same now. Not having Sonar installed will push me into spending all my time on Cubase without a cozy fallback to rely on.

If Sonar resurfaces as some new product or gets a new lease of life some other way, i’ll have the latest Sonar you can have so I’ll have the same options available to me as any other Sonar user. In the meantime I’ll have a DAW with plenty of features that’s still being developed.

LeBassist
Just thinking out loud...
 
1) Capsulize your previous CW work.  Get an export method down-pat. (I have DOS stuff, so lots of work to do)
2) Find your new DAW.  (Seem's like Studio 1 v3 is a fav for Win & Mac).
3) Take your butter Plugins (I have a love grip on Z3TA & Dim, and anything Anderton did,<thks Craig>)
4) Learn what you new DAW like in the was of work flow
5) Figure out where we are all going to meet-up?

That's a very organized plan.  Here's mine so far:
1.  What? SONAR is defunct?!?!?!  How cow, I need a new DAW!!!!  RIGHT NOW!!!!!
2.  Bought Studio One because it was on sale at a great price.
3.  Can't bond with Studio One.
4.  Bought Samplitude because it was on sale at a great price.
5.  Can't bond with Samplitude.
6.  Return to SONAR.