C++11 interface pure virtual destructor

UPD. There is a mark that it is a duplicate of this question. But in that question OP asks HOW to use default to define pure virtual destructor. This question is about what the difference.

In C++ (latest standard if possible) what the real difference between defining pure virtual destructor with empty body implementation and just a empty body (or default)?

Variant 1:

class I1 {public:    virtual ~I1() {}};

Variant 2.1:

class I21 {public:    virtual ~I21() = 0;};I21::~I21() {}

Variant 2.2:

class I22 {public:    virtual ~I22() = 0;};I22::~I22() = default;

Update I found at least 1 difference between Variant 1 and Variants 2.1/2.2:

std::is_abstract::value is false for Variant 1, and true for Variants 2.1 and 2.2.

Demo

May be someone can found difference between 2.1 and 2.2?