Things don't really change in C++, they only add to it, right?
That depends. Old ways of coding still work fine but are considered harmful, e.g. use of NULL instead of nullptr, using raw instead of smart pointers, not making use of C++11 features.
There is also something like
std::auto_ptr which has been deprecated since C++11 and currently looks to leave us completely with C++17. Granted, it's the only thing I can think of right now which could be actively removed.
Note the date, 1994.
Many compilers dropped quite a lot of functionality and custom features when the first standard was introduced.
Many compilers of the era had minimal template support, and those that did had their own custom container classes. All of these were dropped, as the C++ language adopted a modified version of SGI's container library. So everything the book teaches on those will be invalid and cut from the language.
That is the era of 16 bit DOS. Many things will be taught in that book that have been long dead for most programmers. They did not have flat memory back then, you could mark pointers as near/far/huge. Segment:offset addressing was still mandatory and supported by the compiler. And so on.
If the book started sometime after 1998 and respected the first C++ standard then yes, few things would have been cut.
But this book is from long before the first standard. Every compiler was different, and there was no standard. Many were based roughly on Stroustrup's book, documenting AT&T's C++ 2.0 language, but it was more of a guideline than a standard.