TestComplete 15.57 is out - What's New ?

Documentation for 15.56 is still there.

https://support.smartbear.com/testcomplete/docs/general-info/version-history/features-added-to-ver-15-56.html

It looks like 15.57 is a roll back by SmartBear back to TC 15.55
So going to 15.56 is ok just as long as the changes done are not preventing your automation from working as it should.

As far as marking this solved - 15.57 documentation summed it up as either stay on 15.55 or upgrade to 15.57 which is the same thing as TC 15.55.
https://support.smartbear.com/testcomplete/docs/general-info/version-history/features-added-to-ver-15-55.html 

Now we wait to see when SmartBear release the next version and what is added\corrected from try #2 from the developers.