I plan on getting new PC in a few months and reinstall my Sonar X3. Is there an official word
on how to get this done? A moderator reported that Noel says a flat file for authorization would be issued,
but there's no explanation on how to get the flat file.
 
Any details yet?

Hi. For X3, all you need is your serial and activation code (found in your account, if you don't have them already).
No other things to worry about.
All the best.

You might also want to download X3 plus X3e from there as well, to have.
 

You should have already done this. 
Download EVERYTHING from your account page. 
Save it to 3 places 
All you need is the X3e installer and you serial and activation numbers. 
I have a notepade document with every serial number for every software I have. It's on dropbox so it's backed up on 4 computers plus the cloud. 
I also Have X3e and that was going to be my backup if all else failed as it was the last of the open activation versions. 

My last version of X3 is X3d. Is there anywhere for me to get the X3e patch?

mrpippy2
My last version of X3 is X3d. Is there anywhere for me to get the X3e patch?

https://www.cakewalk.com/Support/Knowledge-Base/2007013361/SONAR-X3e-Update
 

Thank you, Zargg!

As a follow up, I have Sonar X3 currently installed and running just fine at present. However, in 2018 I will re-install it on a new pc.
I ask because with the end of Cakewalk as we know it, and the store already closed, will the server used for authorization still be up and running in 3-6 months to perform a reinstall? I don't want to assume anything, that's all.

X3 does not need to be activated via a server. Just make sure you have all your files and go for it.
Make sure you get your serial and registration number from your online account.

Cactus Music
...I have a notepade document with every serial number for every software I have...

 
Me too. I've also save all the software that I have downloaded. It sits there ready in case I need to reinstall anything. I never download anything more than once if I can avoid it.