diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ae903e99..86250e5a6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -55,13 +55,8 @@ ENDIF(WIN32)
 # ----------------------------------------------------
 # --- OPTIONS  ---------------------------------------
 # ----------------------------------------------------
-OPTION (EIGEN_NUMPY_ALIGNED "Directly aligned data between Numpy and Eigen" OFF)
 OPTION (BUILD_UNIT_TESTS "Build the unitary tests" ON)
 
-IF(EIGEN_NUMPY_ALIGNED)
-  ADD_DEFINITIONS(-DEIGENPY_ALIGNED)
-ENDIF(EIGEN_NUMPY_ALIGNED)
-
 # ----------------------------------------------------
 # --- DEPENDANCIES -----------------------------------
 # ----------------------------------------------------
@@ -103,6 +98,7 @@ SET(HEADERS
   registration.hpp
   angle-axis.hpp
   quaternion.hpp
+  stride.hpp
   ref.hpp
 )
 
@@ -157,13 +153,9 @@ ADD_SUBDIRECTORY(python)
 # ----------------------------------------------------
 ADD_SUBDIRECTORY(unittest)
 
-IF(EIGEN_NUMPY_ALIGNED)
-  PKG_CONFIG_APPEND_CFLAGS("-DEIGENPY_ALIGNED")
-ENDIF(EIGEN_NUMPY_ALIGNED)
-
 PKG_CONFIG_APPEND_LIBS(${PROJECT_NAME})
-PKG_CONFIG_APPEND_CFLAGS("-I${PYTHON_INCLUDE_DIRS}")
-PKG_CONFIG_APPEND_CFLAGS("-I${NUMPY_INCLUDE_DIRS}")
+PKG_CONFIG_APPEND_CFLAGS("-isystem ${PYTHON_INCLUDE_DIRS}")
+PKG_CONFIG_APPEND_CFLAGS("-isystem ${NUMPY_INCLUDE_DIRS}")
 PKG_CONFIG_APPEND_BOOST_LIBS(${BOOST_COMPONENTS})
 
 SETUP_PROJECT_FINALIZE()
diff --git a/src/details.hpp b/src/details.hpp
index 6fe8295d2..f99467fc6 100644
--- a/src/details.hpp
+++ b/src/details.hpp
@@ -85,6 +85,7 @@ namespace eigenpy
     }
   };
   
+#if EIGEN_VERSION_AT_LEAST(3,2,0)
   template<typename MatType>
   struct EigenObjectAllocator< eigenpy::Ref<MatType> >
   {
@@ -101,6 +102,7 @@ namespace eigenpy
       MapNumpy<MatType>::map(pyArray) = mat;
     }
   };
+#endif
 
   /* --- TO PYTHON -------------------------------------------------------------- */
   template<typename MatType>
diff --git a/src/eigenpy.hpp b/src/eigenpy.hpp
index 9fcecc7ce..8ecf798f9 100644
--- a/src/eigenpy.hpp
+++ b/src/eigenpy.hpp
@@ -19,12 +19,20 @@
 
 #include "eigenpy/fwd.hpp"
 #include "eigenpy/deprecated.hh"
+#if EIGEN_VERSION_AT_LEAST(3,2,0)
 #include "eigenpy/ref.hpp"
 
 #define ENABLE_SPECIFIC_MATRIX_TYPE(TYPE) \
   enableEigenPySpecific<TYPE>(); \
   enableEigenPySpecific< eigenpy::Ref<TYPE> >();
 
+#else
+
+#define ENABLE_SPECIFIC_MATRIX_TYPE(TYPE) \
+  enableEigenPySpecific<TYPE>();
+
+#endif
+
 namespace eigenpy
 {
   /* Enable Eigen-Numpy serialization for a set of standard MatrixBase instance. */
diff --git a/src/fwd.hpp b/src/fwd.hpp
index d5d1f2e66..5f00431f6 100644
--- a/src/fwd.hpp
+++ b/src/fwd.hpp
@@ -28,9 +28,14 @@
 #include <numpy/noprefix.h>
 
 #ifdef NPY_ALIGNED
-#define EIGENPY_DEFAULT_ALIGNMENT_VALUE Eigen::Aligned16
+#if EIGEN_VERSION_AT_LEAST(3,2,90)
+  #define EIGENPY_DEFAULT_ALIGNMENT_VALUE Eigen::Aligned16
 #else
-#define EIGENPY_DEFAULT_ALIGNMENT_VALUE Eigen::Unaligned
+  #define EIGENPY_DEFAULT_ALIGNMENT_VALUE Eigen::Aligned
+#endif
+#else
+  #define EIGENPY_DEFAULT_ALIGNMENT_VALUE Eigen::Unaligned
 #endif
 
 #endif // ifndef __eigenpy_fwd_hpp__
+
diff --git a/src/map.hpp b/src/map.hpp
index 2a2fb4b27..c7414355d 100644
--- a/src/map.hpp
+++ b/src/map.hpp
@@ -17,6 +17,7 @@
 #include "eigenpy/fwd.hpp"
 #include <numpy/arrayobject.h>
 #include "eigenpy/exception.hpp"
+#include "eigenpy/stride.hpp"
 
 namespace eigenpy
 {
diff --git a/src/ref.hpp b/src/ref.hpp
index 641228e18..367bf0f8a 100644
--- a/src/ref.hpp
+++ b/src/ref.hpp
@@ -18,27 +18,17 @@
 #define __eigenpy_ref_hpp__
 
 #include "eigenpy/fwd.hpp"
+#include "eigenpy/stride.hpp"
 
 // For old Eigen versions, EIGEN_DEVICE_FUNC is not defined.
 // We must define it just in the scope of this file.
-#if not EIGEN_VERSION_AT_LEAST(3,2,91)
+#if not EIGEN_VERSION_AT_LEAST(3,2,90)
 #define EIGEN_DEVICE_FUNC
 #endif
 
 namespace eigenpy
 {
-  template<typename MatType, int IsVectorAtCompileTime = MatType::IsVectorAtCompileTime>
-  struct StrideType
-  {
-    typedef Eigen::Stride<Eigen::Dynamic,Eigen::Dynamic> type;
-  };
-  
-  template<typename MatType>
-  struct StrideType<MatType,1>
-  {
-    typedef Eigen::InnerStride<Eigen::Dynamic> type;
-  };
-  
+
   template<typename PlainObjectType>
   struct Ref : Eigen::Ref<PlainObjectType,EIGENPY_DEFAULT_ALIGNMENT_VALUE,typename StrideType<PlainObjectType>::type>
   {
@@ -58,7 +48,7 @@ namespace eigenpy
     typedef typename Base::CoeffReturnType CoeffReturnType; /*!< \brief The return type for coefficient access. \details Depending on whether the object allows direct coefficient access (e.g. for a MatrixXd), this type is either 'const Scalar&' or simply 'Scalar' for objects that do not allow direct coefficient access. */
     typedef typename Eigen::internal::ref_selector<Base>::type Nested;
     typedef typename Eigen::internal::traits<Base>::StorageKind StorageKind;
-#if EIGEN_VERSION_AT_LEAST(3,2,91)
+#if EIGEN_VERSION_AT_LEAST(3,2,90)
     typedef typename Eigen::internal::traits<Base>::StorageIndex StorageIndex;
 #else
     typedef typename Eigen::internal::traits<Base>::Index StorageIndex;
@@ -104,7 +94,7 @@ namespace eigenpy
   }; // struct Ref<PlainObjectType>
 }
 
-#if not EIGEN_VERSION_AT_LEAST(3,2,91)
+#if not EIGEN_VERSION_AT_LEAST(3,2,90)
 #undef EIGEN_DEVICE_FUNC
 #endif
 
diff --git a/src/solvers/preconditioners.cpp b/src/solvers/preconditioners.cpp
index fb2f2e35a..1854170f7 100644
--- a/src/solvers/preconditioners.cpp
+++ b/src/solvers/preconditioners.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017, Justin Carpentier, LAAS-CNRS
+ * Copyright 2017-2018, Justin Carpentier, LAAS-CNRS
  *
  * This file is part of eigenpy.
  * eigenpy is free software: you can redistribute it and/or
@@ -14,12 +14,16 @@
  * with eigenpy.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <Eigen/Core>
+
+#if EIGEN_VERSION_AT_LEAST(3,2,0)
 #include "eigenpy/solvers/preconditioners.hpp"
 #include "eigenpy/solvers/BasicPreconditioners.hpp"
 //#include "eigenpy/solvers/BFGSPreconditioners.hpp"
 
 namespace eigenpy
 {
+
   void exposePreconditioners()
   {
     using namespace Eigen;
@@ -32,4 +36,8 @@ namespace eigenpy
 //      LimitedBFGSPreconditionerBaseVisitor< LimitedBFGSPreconditioner<double,Eigen::Dynamic,Eigen::Upper|Eigen::Lower> >::expose("LimitedBFGSPreconditioner");
    
   }
+
 } // namespace eigenpy
+
+#endif
+
diff --git a/src/solvers/solvers.cpp b/src/solvers/solvers.cpp
index d0d7103ff..8a30217dd 100644
--- a/src/solvers/solvers.cpp
+++ b/src/solvers/solvers.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017, Justin Carpentier, LAAS-CNRS
+ * Copyright 2017-2018, Justin Carpentier, LAAS-CNRS
  *
  * This file is part of eigenpy.
  * eigenpy is free software: you can redistribute it and/or
@@ -14,6 +14,10 @@
  * with eigenpy.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <Eigen/Core>
+
+#if EIGEN_VERSION_AT_LEAST(3,2,0)
+
 #include "eigenpy/solvers/solvers.hpp"
 #include "eigenpy/solvers/ConjugateGradient.hpp"
 
@@ -43,3 +47,6 @@ namespace eigenpy
     ;
   }
 } // namespace eigenpy
+
+#endif
+
diff --git a/src/stride.hpp b/src/stride.hpp
new file mode 100644
index 000000000..438b818aa
--- /dev/null
+++ b/src/stride.hpp
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2018, Justin Carpentier <jcarpent@laas.fr>, LAAS-CNRS
+ *
+ * This file is part of eigenpy.
+ * eigenpy is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ * eigenpy is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.  You should
+ * have received a copy of the GNU Lesser General Public License along
+ * with eigenpy.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __eigenpy_stride_hpp__
+#define __eigenpy_stride_hpp__
+
+#include <Eigen/Core>
+
+namespace eigenpy
+{
+  template<typename MatType, int IsVectorAtCompileTime = MatType::IsVectorAtCompileTime>
+  struct StrideType
+  {
+    typedef Eigen::Stride<Eigen::Dynamic,Eigen::Dynamic> type;
+  };
+  
+  template<typename MatType>
+  struct StrideType<MatType,1>
+  {
+    typedef Eigen::InnerStride<Eigen::Dynamic> type;
+  };
+}
+
+#endif // ifndef __eigenpy_stride_hpp__
diff --git a/unittest/CMakeLists.txt b/unittest/CMakeLists.txt
index 8b0a15c8e..76a817fd5 100644
--- a/unittest/CMakeLists.txt
+++ b/unittest/CMakeLists.txt
@@ -40,5 +40,7 @@ ADD_CUSTOM_TARGET(check COMMAND ${CMAKE_CTEST_COMMAND})
 
 ADD_LIB_UNIT_TEST(matrix "eigen3")
 ADD_LIB_UNIT_TEST(geometry "eigen3")
-ADD_LIB_UNIT_TEST(ref "eigen3")
+IF(NOT ${EIGEN3_VERSION} VERSION_LESS "3.2.0")
+  ADD_LIB_UNIT_TEST(ref "eigen3")
+ENDIF()