NOTE: HOW TO KEEP YOUR OLD SAVE FILES
If you are using .exe or .dmg version (android and online versions are doing it automatically), just overwrite your old simbro.exe with a new one (You should get windows prompt asking you if you want to overwrite the file). Keeping it in the same place old file was located.
Also you can find and backup your save files at:
Users -> %user name%->AppData->Roaming->Macromedia->Flash Player->#SharedObjects ->%Random letters%->localhost->%path to your simbro.exe file%->simbro.swf->
Where you'll find slot_0.sol, slot_1.sol, slot_2.sol files, which are the save files themselves.
Q - "Why did you put them at such a complicated path?"
A - It's Flash Player thing, we cannot change it so far =(
NOTE: HOW TO FIX MAC SIERRA OS ISSUE
There is a description of the method - https://discussions.apple.com/thread/4805609?tstart=0
After downloading .dmg file system gives him attributes that file was downloaded from the internet. So press cmd-space and start typing "terminal" to get suggestion for that program. Press enter and type "xattr - c " then drag n drop the simbro.dmg to the terminal screen to get it's path. Then press enter. It could ask you for Administrator password to confirm the action. Don't worry, xattr it's just an utility to change file's attributes, here is the description: https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/xattr.1.html
You don't have to enter " itself, just a text inside. It would be faster solution then to wait while we get through licence procedure for apple developers.