fixed pypy minimum version

README.md

@@ -25,7 +25,7 @@ become an excessively large and unnecessary dependency.
 Think of this library as a tiny self-contained version of Boost.Python with
 everything stripped away that isn't relevant for binding generation. Without
 comments, the core header files only require ~2.5K lines of code and depend on
-Python (2.7 or 3.x, or PyPy2.7 >= 5.5) and the C++ standard library. This compact implementation
+Python (2.7 or 3.x, or PyPy2.7 >= 5.7) and the C++ standard library. This compact implementation
 was possible thanks to some of the new C++11 language features (specifically:
 tuples, lambda functions and variadic templates). Since its creation, this
 library has grown beyond Boost.Python in many ways, leading to dramatically
@@ -58,7 +58,7 @@ pybind11 can map the following core C++ features to Python
 ## Goodies
 In addition to the core functionality, pybind11 provides some extra goodies:
 
-- Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.5) are supported with an
+- Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.7) are supported with an
   implementation-agnostic interface.
 
 - It is possible to bind C++11 lambda functions with captured variables. The

docs/intro.rst

@@ -51,7 +51,7 @@ Goodies
 *******
 In addition to the core functionality, pybind11 provides some extra goodies:
 
-- Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.5) are supported with an
+- Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.7) are supported with an
   implementation-agnostic interface.
 
 - It is possible to bind C++11 lambda functions with captured variables. The