Upgrade to Flash 20 dated 12/28/15 causes Xcelsius 2008 to fail

I have used Xcelsius 2008 since, well, 2008, and it was working fine yesterday with Adobe Flash 20 released 12/11/15 (20.0.0.228).

My browsers (Firefox and IE) demanded that I upgrade to the new version dated 12/28/15 to fix security vulnerabilities.

Now when I start Xcelsius 2008 all the of the file functions are grayed out, so I cannot open any files or update them.The new version of Flash seems to have crippled Xcelsius 2008 which uses both Flash and AIR.

When I do the same thing on my backup system it works fine because that is still on Flash 20.0.0.228.

I use Xcelsius 2008 every day for several hours and I am now out of action. Can anyone advise how I can get hold of the old version of Flash and re-install it?

Thanks