Corelcad 15 vs Corelcad 17? and general questions

Hello and good day..  I am assuming that Corel has stopped making Corel Inventor and has now replaced it with the CorelCad product?  

Is there a lot of difference between the 2015 version of CC vs the 2017 version?  If 2015 works well enough I don't mind missing a few bells or whistles in the later versions.. Anyone know about the diffrences and or issues with the older version?

Also, if this is a replacment for inventor is there any issues that would make you want inventor back? or cause you to look at autodesk or paying the big bucks and going to solidworks.  I would love to have solidworks, but they make it nearly impossible for the small guy to own and use it..

Appreciate any input on this..   thank you for your time

String