2013 --> 2015 change in reading reals?

I'm sure this is just a compiler setting or something, but I'm rusty!  When we moved from 2013 to 2015, our applications stopped working properly.  We tracked it down to the fact that we were trying to read integers (or a delimited integer - e.g. '1') into a real.  In 2013 this worked.  In 2015 it's blowing up on us.  Any ideas?

Thanks!

Brad.