Though we don’t officially support it, but we know of users running Dorico successfully on Win7.
We now have a Win7 user who contacted our support where after the update to Dorico 1.1 the audio engine suddenly doesn’t work anymore at all.
So, what is your experience with Dorico 1.1 and Win7?
I have never had any probs with the Audio engine since I first got it working on Dorico’s initial release. I use Win 7 and have updated to 1.1 and now to 1.1.10 without problems.
I was unaware of this. I have reverted to Windows 7 on my desktop, and have had no problems. As I have written elsewhere (Screen resolution issues - Dorico - Steinberg Forums), I dont find my Windows 10 laptop to be of much use for Dorico on account of screen resolution issues and the consequently small amount of screen space left for the score.
David
Thanks guys for your quick feedback.
I also installed it here on a freshly installed Win7 machine and it did work fine.
So I’m glad that it is not a general issue but specific to just that user’s setup.
Also I am glad to say that Dorico 1.1.10 and the audio engine run just fine here under Windows 7 64-bit. 
Je travaille avec windows 7 pour Dorico depuis novembre 2016 et cela marche même avec les dernières mise à jour. Le problème avec les sons ont été résolus