I'm speaking strictly technical here, but there have been features that have been removed. Trigraphs (I think), and the register keyword. Moreover, there are objects that are very clearly marked deprecated, like auto_ptr. (Oh, and there is even talk of removing 'volatile' as a keyword.)

The register keyword issue crops up because legacy code included and linked to modern C++ will occasionally have the word "register" affixed to a loop variable. Generally speaking, once you change standards, there is room to drop the old stuff. It's just gradual. Static analyzers do a lot to modernize code now too, so the situation is not as painful as it used to be.