diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0c67b52a..44489b44 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -34,25 +34,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Introduction of namespaces for all classes, eg: `PHPExcel_Calculation_Function` becomes `PhpOffice\PhpSpreadsheet\Calculation\Functions`
 - Some classes were renamed for clarity and/or consistency:
 
-| Before                          | After                                     |
-|---------------------------------|-------------------------------------------|
-| `PHPExcel`                      | `PhpOffice\PhpSpreadsheet\Spreadsheet`    |
-| `PHPExcel_Reader_Excel2007`     | `PhpOffice\PhpSpreadsheet\Reader\Xlsx`    |
-| `PHPExcel_Reader_Excel5`        | `PhpOffice\PhpSpreadsheet\Reader\Xls`     |
-| `PHPExcel_Reader_OOcalc`        | `PhpOffice\PhpSpreadsheet\Reader\Ods`     |
-| `PHPExcel_Writer_Excel2007`     | `PhpOffice\PhpSpreadsheet\Writer\Xlsx`    |
-| `PHPExcel_Writer_Excel5`        | `PhpOffice\PhpSpreadsheet\Writer\Xls`     |
-| `PHPExcel_Writer_OpenOffice`    | `PhpOffice\PhpSpreadsheet\Writer\Ods`     |
-
-- Some methods were renamed for clarity and/or consistency:
-
-| Before                                           | After                                                      |
-|--------------------------------------------------|------------------------------------------------------------|
-| `PHPExcel_Calculation_DateTime::DAYOFWEEK()`     | `PhpOffice\PhpSpreadsheet\Calculation\DateTime::WEEKDAY()` |
-| `PHPExcel_Calculation_DateTime::WEEKOFYEAR()`    | `PhpOffice\PhpSpreadsheet\Calculation\DateTime::WEEKNUM()` |
-| `PHPExcel_Calculation_DateTime::MINUTEOFHOUR()`  | `PhpOffice\PhpSpreadsheet\Calculation\DateTime::MINUTE()`  |
-| `PHPExcel_Calculation_DateTime::SECONDOFMINUTE()`| `PhpOffice\PhpSpreadsheet\Calculation\DateTime::SECOND()`  |
-
+For a comprehensive list of all class changes, and a semi-automated migration path, read the [migration guide](./docs/Migration-from-PHPExcel.md).
 
 ## [1.8.1] - 2015-04-30
 
diff --git a/docs/Migration-from-PHPExcel.md b/docs/Migration-from-PHPExcel.md
new file mode 100644
index 00000000..e170607b
--- /dev/null
+++ b/docs/Migration-from-PHPExcel.md
@@ -0,0 +1,17 @@
+# Migration from PHPExcel
+
+PhpSpreadsheet introduced many breaking changes by introducing namespaces and
+renaming some classes. To help you migrate existing project, a tool was written
+to replace all references to PHPExcel classes to their new names.
+
+The tool is included in PhpSpreadsheet. It scans recursively all files and
+directories, starting from the current directory. Assuming it was installed with
+composer, it can be run like so:
+
+```sh
+cd /project/to/migrate/src
+/project/to/migrate/vendor/phpoffice/phpspreadsheet/bin/migrate-from-phpexcel
+```
+
+**Important** The tool will irreversibly modify your sources, be sure to backup
+everything, and double check the result before committing.
\ No newline at end of file
diff --git a/docs/README.md b/docs/index.md
similarity index 100%
rename from docs/README.md
rename to docs/index.md
diff --git a/src/PhpSpreadsheet/Chart/Renderer/JpGraph.php b/src/PhpSpreadsheet/Chart/Renderer/JpGraph.php
index a3b54d1f..f9d3d17d 100644
--- a/src/PhpSpreadsheet/Chart/Renderer/JpGraph.php
+++ b/src/PhpSpreadsheet/Chart/Renderer/JpGraph.php
@@ -2,8 +2,6 @@
 
 namespace PhpOffice\PhpSpreadsheet\Chart\Renderer;
 
-require_once \PhpOffice\PhpSpreadsheet\Settings::getChartRendererPath() . '/jpgraph.php';
-
 /**
  * Copyright (c) 2006 - 2016 PhpSpreadsheet
  *
@@ -854,5 +852,7 @@ class JpGraph
     {
         $this->graph = null;
         $this->chart = $chart;
+
+        require_once \PhpOffice\PhpSpreadsheet\Settings::getChartRendererPath() . '/jpgraph.php';
     }
 }
diff --git a/src/PhpSpreadsheet/Helper/Migrator.php b/src/PhpSpreadsheet/Helper/Migrator.php
new file mode 100644
index 00000000..289e5640
--- /dev/null
+++ b/src/PhpSpreadsheet/Helper/Migrator.php
@@ -0,0 +1,281 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Helper;
+
+class Migrator
+{
+    /**
+     * Return the ordered mapping from old PHPExcel class names to new PhpSpreadsheet one
+     * @return string[]
+     */
+    public function getMapping()
+    {
+        // Order matters here, we should have the deepest namespaces first (the most "unique" strings)
+        $mapping = [
+            'PHPExcel_Shared_Escher_DggContainer_BstoreContainer_BSE_Blip' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DggContainer\\BstoreContainer\\BSE\\Blip',
+            'PHPExcel_Shared_Escher_DgContainer_SpgrContainer_SpContainer' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DgContainer\\SpgrContainer\\SpContainer',
+            'PHPExcel_Shared_Escher_DggContainer_BstoreContainer_BSE' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DggContainer\\BstoreContainer\\BSE',
+            'PHPExcel_Shared_Escher_DgContainer_SpgrContainer' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DgContainer\\SpgrContainer',
+            'PHPExcel_Shared_Escher_DggContainer_BstoreContainer' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DggContainer\\BstoreContainer',
+            'PHPExcel_Shared_OLE_PPS_File' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLE\\PPS\\File',
+            'PHPExcel_Shared_OLE_PPS_Root' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLE\\PPS\\Root',
+            'PHPExcel_Worksheet_AutoFilter_Column_Rule' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\AutoFilter\\Column\\Rule',
+            'PHPExcel_Writer_OpenDocument_Cell_Comment' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Cell\\Comment',
+            'PHPExcel_Calculation_Token_Stack' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Token\\Stack',
+            'PHPExcel_Chart_Renderer_jpgraph' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Renderer\\JpGraph',
+            'PHPExcel_Reader_Excel5_Escher' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xls\\Escher',
+            'PHPExcel_Reader_Excel5_MD5' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xls\\MD5',
+            'PHPExcel_Reader_Excel5_RC4' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xls\\RC4',
+            'PHPExcel_Reader_Excel2007_Chart' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xlsx\\Chart',
+            'PHPExcel_Reader_Excel2007_Theme' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xlsx\\Theme',
+            'PHPExcel_Shared_Escher_DgContainer' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DgContainer',
+            'PHPExcel_Shared_Escher_DggContainer' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher\\DggContainer',
+            'CholeskyDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\CholeskyDecomposition',
+            'EigenvalueDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\EigenvalueDecomposition',
+            'PHPExcel_Shared_JAMA_LUDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\LUDecomposition',
+            'PHPExcel_Shared_JAMA_Matrix' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\Matrix',
+            'QRDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\QRDecomposition',
+            'PHPExcel_Shared_JAMA_QRDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\QRDecomposition',
+            'SingularValueDecomposition' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\JAMA\\SingularValueDecomposition',
+            'PHPExcel_Shared_OLE_ChainedBlockStream' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLE\\ChainedBlockStream',
+            'PHPExcel_Shared_OLE_PPS' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLE\\PPS',
+            'PclZip' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\PCLZip\\PclZip',
+            'PHPExcel_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\BestFit',
+            'PHPExcel_Exponential_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\ExponentialBestFit',
+            'PHPExcel_Linear_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\LinearBestFit',
+            'PHPExcel_Logarithmic_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\LogarithmicBestFit',
+            'polynomialBestFit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\PolynomialBestFit',
+            'PHPExcel_Polynomial_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\PolynomialBestFit',
+            'powerBestFit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\PowerBestFit',
+            'PHPExcel_Power_Best_Fit' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\PowerBestFit',
+            'trendClass' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Trend\\Trend',
+            'PHPExcel_Worksheet_AutoFilter_Column' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\AutoFilter\\Column',
+            'PHPExcel_Worksheet_Drawing_Shadow' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Drawing\\Shadow',
+            'PHPExcel_Writer_OpenDocument_Content' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Content',
+            'PHPExcel_Writer_OpenDocument_Meta' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Meta',
+            'PHPExcel_Writer_OpenDocument_MetaInf' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\MetaInf',
+            'PHPExcel_Writer_OpenDocument_Mimetype' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Mimetype',
+            'PHPExcel_Writer_OpenDocument_Settings' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Settings',
+            'PHPExcel_Writer_OpenDocument_Styles' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Styles',
+            'PHPExcel_Writer_OpenDocument_Thumbnails' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Thumbnails',
+            'PHPExcel_Writer_OpenDocument_WriterPart' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\WriterPart',
+            'PHPExcel_Writer_PDF_Core' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\Core',
+            'PHPExcel_Writer_PDF_DomPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\DomPDF',
+            'PHPExcel_Writer_PDF_mPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\MPDF',
+            'PHPExcel_Writer_PDF_tcPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\TcPDF',
+            'PHPExcel_Writer_Excel5_BIFFwriter' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\BIFFwriter',
+            'PHPExcel_Writer_Excel5_Escher' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Escher',
+            'PHPExcel_Writer_Excel5_Font' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Font',
+            'PHPExcel_Writer_Excel5_Parser' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Parser',
+            'PHPExcel_Writer_Excel5_Workbook' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Workbook',
+            'PHPExcel_Writer_Excel5_Worksheet' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Worksheet',
+            'PHPExcel_Writer_Excel5_Xf' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Xf',
+            'PHPExcel_Writer_Excel2007_Chart' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Chart',
+            'PHPExcel_Writer_Excel2007_Comments' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Comments',
+            'PHPExcel_Writer_Excel2007_ContentTypes' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\ContentTypes',
+            'PHPExcel_Writer_Excel2007_DocProps' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\DocProps',
+            'PHPExcel_Writer_Excel2007_Drawing' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Drawing',
+            'PHPExcel_Writer_Excel2007_Rels' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Rels',
+            'PHPExcel_Writer_Excel2007_RelsRibbon' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\RelsRibbon',
+            'PHPExcel_Writer_Excel2007_RelsVBA' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\RelsVBA',
+            'PHPExcel_Writer_Excel2007_StringTable' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\StringTable',
+            'PHPExcel_Writer_Excel2007_Style' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Style',
+            'PHPExcel_Writer_Excel2007_Theme' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Theme',
+            'PHPExcel_Writer_Excel2007_Workbook' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Workbook',
+            'PHPExcel_Writer_Excel2007_Worksheet' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\Worksheet',
+            'PHPExcel_Writer_Excel2007_WriterPart' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx\\WriterPart',
+            'PHPExcel_CachedObjectStorage_APC' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\APC',
+            'PHPExcel_CachedObjectStorage_CacheBase' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\CacheBase',
+            'PHPExcel_CachedObjectStorage_DiscISAM' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\DiscISAM',
+            'PHPExcel_CachedObjectStorage_ICache' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\ICache',
+            'PHPExcel_CachedObjectStorage_Igbinary' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\Igbinary',
+            'PHPExcel_CachedObjectStorage_Memcache' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\Memcache',
+            'PHPExcel_CachedObjectStorage_Memory' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\Memory',
+            'PHPExcel_CachedObjectStorage_MemoryGZip' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\MemoryGZip',
+            'PHPExcel_CachedObjectStorage_MemorySerialized' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\MemorySerialized',
+            'PHPExcel_CachedObjectStorage_PHPTemp' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\PHPTemp',
+            'PHPExcel_CachedObjectStorage_SQLite' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\SQLite',
+            'PHPExcel_CachedObjectStorage_SQLite3' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\SQLite3',
+            'PHPExcel_CachedObjectStorage_Wincache' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorage\\Wincache',
+            'PHPExcel_CalcEngine_CyclicReferenceStack' => '\\PhpOffice\\PhpSpreadsheet\\CalcEngine\\CyclicReferenceStack',
+            'PHPExcel_CalcEngine_Logger' => '\\PhpOffice\\PhpSpreadsheet\\CalcEngine\\Logger',
+            'PHPExcel_Calculation_Functions' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Functions',
+            'PHPExcel_Calculation_Function' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Categories',
+            'PHPExcel_Calculation_Database' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Database',
+            'PHPExcel_Calculation_DateTime' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\DateTime',
+            'PHPExcel_Calculation_Engineering' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Engineering',
+            'PHPExcel_Calculation_Exception' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Exception',
+            'PHPExcel_Calculation_ExceptionHandler' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\ExceptionHandler',
+            'PHPExcel_Calculation_Financial' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Financial',
+            'PHPExcel_Calculation_FormulaParser' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\FormulaParser',
+            'PHPExcel_Calculation_FormulaToken' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\FormulaToken',
+            'PHPExcel_Calculation_Logical' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Logical',
+            'PHPExcel_Calculation_LookupRef' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\LookupRef',
+            'PHPExcel_Calculation_MathTrig' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\MathTrig',
+            'PHPExcel_Calculation_Statistical' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\Statistical',
+            'PHPExcel_Calculation_TextData' => '\\PhpOffice\\PhpSpreadsheet\\Calculation\\TextData',
+            'PHPExcel_Cell_AdvancedValueBinder' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\AdvancedValueBinder',
+            'PHPExcel_Cell_DataType' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\DataType',
+            'PHPExcel_Cell_DataValidation' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\DataValidation',
+            'PHPExcel_Cell_DefaultValueBinder' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\DefaultValueBinder',
+            'PHPExcel_Cell_Hyperlink' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\Hyperlink',
+            'PHPExcel_Cell_IValueBinder' => '\\PhpOffice\\PhpSpreadsheet\\Cell\\IValueBinder',
+            'PHPExcel_Chart_Axis' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Axis',
+            'PHPExcel_Chart_DataSeries' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\DataSeries',
+            'PHPExcel_Chart_DataSeriesValues' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\DataSeriesValues',
+            'PHPExcel_Chart_Exception' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Exception',
+            'PHPExcel_Chart_GridLines' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\GridLines',
+            'PHPExcel_Chart_Layout' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Layout',
+            'PHPExcel_Chart_Legend' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Legend',
+            'PHPExcel_Chart_PlotArea' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\PlotArea',
+            'PHPExcel_Properties' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Properties',
+            'PHPExcel_Chart_Title' => '\\PhpOffice\\PhpSpreadsheet\\Chart\\Title',
+            'PHPExcel_DocumentProperties' => '\\PhpOffice\\PhpSpreadsheet\\Document\\Properties',
+            'PHPExcel_DocumentSecurity' => '\\PhpOffice\\PhpSpreadsheet\\Document\\Security',
+            'PHPExcel_Helper_HTML' => '\\PhpOffice\\PhpSpreadsheet\\Helper\\HTML',
+            'PHPExcel_Reader_Abstract' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\BaseReader',
+            'PHPExcel_Reader_CSV' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\CSV',
+            'PHPExcel_Reader_DefaultReadFilter' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\DefaultReadFilter',
+            'PHPExcel_Reader_Excel2003XML' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Excel2003XML',
+            'PHPExcel_Reader_Exception' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Exception',
+            'PHPExcel_Reader_Gnumeric' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Gnumeric',
+            'PHPExcel_Reader_HTML' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\HTML',
+            'PHPExcel_Reader_IReadFilter' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\IReadFilter',
+            'PHPExcel_Reader_IReader' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\IReader',
+            'PHPExcel_Reader_OOCalc' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Ods',
+            'PHPExcel_Reader_SYLK' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\SYLK',
+            'PHPExcel_Reader_Excel5' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xls',
+            'PHPExcel_Reader_Excel2007' => '\\PhpOffice\\PhpSpreadsheet\\Reader\\Xlsx',
+            'PHPExcel_RichText_ITextElement' => '\\PhpOffice\\PhpSpreadsheet\\RichText\\ITextElement',
+            'PHPExcel_RichText_Run' => '\\PhpOffice\\PhpSpreadsheet\\RichText\\Run',
+            'PHPExcel_RichText_TextElement' => '\\PhpOffice\\PhpSpreadsheet\\RichText\\TextElement',
+            'PHPExcel_Shared_CodePage' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\CodePage',
+            'PHPExcel_Shared_Date' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Date',
+            'PHPExcel_Shared_Drawing' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Drawing',
+            'PHPExcel_Shared_Escher' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Escher',
+            'PHPExcel_Shared_File' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\File',
+            'PHPExcel_Shared_Font' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Font',
+            'PHPExcel_Shared_OLE' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLE',
+            'PHPExcel_Shared_OLERead' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\OLERead',
+            'PHPExcel_Shared_PasswordHasher' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\PasswordHasher',
+            'PHPExcel_Shared_String' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\StringHelper',
+            'PHPExcel_Shared_TimeZone' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\TimeZone',
+            'PHPExcel_Shared_XMLWriter' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\XMLWriter',
+            'PHPExcel_Shared_Excel5' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\Xls',
+            'PHPExcel_Shared_ZipArchive' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\ZipArchive',
+            'PHPExcel_Shared_ZipStreamWrapper' => '\\PhpOffice\\PhpSpreadsheet\\Shared\\ZipStreamWrapper',
+            'PHPExcel_Style_Alignment' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Alignment',
+            'PHPExcel_Style_Border' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Border',
+            'PHPExcel_Style_Borders' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Borders',
+            'PHPExcel_Style_Color' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Color',
+            'PHPExcel_Style_Conditional' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Conditional',
+            'PHPExcel_Style_Fill' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Fill',
+            'PHPExcel_Style_Font' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Font',
+            'PHPExcel_Style_NumberFormat' => '\\PhpOffice\\PhpSpreadsheet\\Style\\NumberFormat',
+            'PHPExcel_Style_Protection' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Protection',
+            'PHPExcel_Style_Supervisor' => '\\PhpOffice\\PhpSpreadsheet\\Style\\Supervisor',
+            'PHPExcel_Worksheet_AutoFilter' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\AutoFilter',
+            'PHPExcel_Worksheet_BaseDrawing' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\BaseDrawing',
+            'PHPExcel_Worksheet_CellIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\CellIterator',
+            'PHPExcel_Worksheet_Column' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Column',
+            'PHPExcel_Worksheet_ColumnCellIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\ColumnCellIterator',
+            'PHPExcel_Worksheet_ColumnDimension' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\ColumnDimension',
+            'PHPExcel_Worksheet_ColumnIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\ColumnIterator',
+            'PHPExcel_Worksheet_Drawing' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Drawing',
+            'PHPExcel_Worksheet_HeaderFooter' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\HeaderFooter',
+            'PHPExcel_Worksheet_HeaderFooterDrawing' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\HeaderFooterDrawing',
+            'PHPExcel_WorksheetIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Iterator',
+            'PHPExcel_Worksheet_MemoryDrawing' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\MemoryDrawing',
+            'PHPExcel_Worksheet_PageMargins' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\PageMargins',
+            'PHPExcel_Worksheet_PageSetup' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\PageSetup',
+            'PHPExcel_Worksheet_Protection' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Protection',
+            'PHPExcel_Worksheet_Row' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\Row',
+            'PHPExcel_Worksheet_RowCellIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\RowCellIterator',
+            'PHPExcel_Worksheet_RowDimension' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\RowDimension',
+            'PHPExcel_Worksheet_RowIterator' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\RowIterator',
+            'PHPExcel_Worksheet_SheetView' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet\\SheetView',
+            'PHPExcel_Writer_Abstract' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\BaseWriter',
+            'PHPExcel_Writer_CSV' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\CSV',
+            'PHPExcel_Writer_Exception' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Exception',
+            'PHPExcel_Writer_HTML' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\HTML',
+            'PHPExcel_Writer_IWriter' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\IWriter',
+            'PHPExcel_Writer_OpenDocument' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods',
+            'PHPExcel_Writer_PDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF',
+            'PHPExcel_Writer_Excel5' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls',
+            'PHPExcel_Writer_Excel2007' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx',
+            'PHPExcel_Autoloader' => '\\PhpOffice\\PhpSpreadsheet\\Autoloader',
+            'PHPExcel_CachedObjectStorageFactory' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorageFactory',
+            'PHPExcel_Calculation' => '\\PhpOffice\\PhpSpreadsheet\\Calculation',
+            'PHPExcel_Cell' => '\\PhpOffice\\PhpSpreadsheet\\Cell',
+            'PHPExcel_Chart' => '\\PhpOffice\\PhpSpreadsheet\\Chart',
+            'PHPExcel_Comment' => '\\PhpOffice\\PhpSpreadsheet\\Comment',
+            'PHPExcel_Exception' => '\\PhpOffice\\PhpSpreadsheet\\Exception',
+            'PHPExcel_HashTable' => '\\PhpOffice\\PhpSpreadsheet\\HashTable',
+            'PHPExcel_IComparable' => '\\PhpOffice\\PhpSpreadsheet\\IComparable',
+            'PHPExcel_IOFactory' => '\\PhpOffice\\PhpSpreadsheet\\IOFactory',
+            'PHPExcel_NamedRange' => '\\PhpOffice\\PhpSpreadsheet\\NamedRange',
+            'PHPExcel_ReferenceHelper' => '\\PhpOffice\\PhpSpreadsheet\\ReferenceHelper',
+            'PHPExcel_RichText' => '\\PhpOffice\\PhpSpreadsheet\\RichText',
+            'PHPExcel_Settings' => '\\PhpOffice\\PhpSpreadsheet\\Settings',
+            'PHPExcel_Style' => '\\PhpOffice\\PhpSpreadsheet\\Style',
+            'PHPExcel_Worksheet' => '\\PhpOffice\\PhpSpreadsheet\\Worksheet',
+            'PHPExcel' => '\\PhpOffice\\PhpSpreadsheet\\Spreadsheet',
+            // methods
+            'MINUTEOFHOUR' => 'MINUTE',
+            'SECONDOFMINUTE' => 'SECOND',
+            'DAYOFWEEK' => 'WEEKDAY',
+            'WEEKOFYEAR' => 'WEEKNUM',
+        ];
+
+        return $mapping;
+    }
+
+    /**
+     * Search in all files in given directory
+     * @param string $path
+     */
+    private function recursiveReplace($path)
+    {
+        $patterns = [
+            '/*.md',
+            '/*.php',
+            '/*.txt',
+            '/*.TXT',
+        ];
+
+        $from = array_keys($this->getMapping());
+        $to = array_values($this->getMapping());
+
+        foreach ($patterns as $pattern) {
+            foreach (glob($path . $pattern) as $file) {
+                $original = file_get_contents($file);
+                $converted = str_replace($from, $to, $original);
+
+                if ($original !== $converted) {
+                    echo $file . " converted\n";
+                    file_put_contents($file, $converted);
+                }
+            }
+        }
+
+        // Do the recursion in subdirectory
+        foreach (glob($path . '/*', GLOB_ONLYDIR) as $subpath) {
+            if (strpos($subpath, $path . '/') === 0) {
+                $this->recursiveReplace($subpath);
+            }
+        }
+    }
+
+    public function migrate()
+    {
+        $path = realpath(getcwd());
+        echo 'This will search and replace recursively in ' . $path . PHP_EOL;
+        echo 'You MUST backup your files first, or you risk losing data.' . PHP_EOL;
+        echo 'Are you sure ? (y/n)';
+
+        $confirm = fread(STDIN, 1);
+        if ($confirm === 'y') {
+            $this->recursiveReplace($path);
+        }
+    }
+}
diff --git a/src/PhpSpreadsheet/Writer/PDF/DomPDF.php b/src/PhpSpreadsheet/Writer/PDF/DomPDF.php
index 320bca45..eba8c7ed 100644
--- a/src/PhpSpreadsheet/Writer/PDF/DomPDF.php
+++ b/src/PhpSpreadsheet/Writer/PDF/DomPDF.php
@@ -2,14 +2,6 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
 
-/*  Require DomPDF library */
-$pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/dompdf_config.inc.php';
-if (file_exists($pdfRendererClassFile)) {
-    require_once $pdfRendererClassFile;
-} else {
-    throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
-}
-
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet
  *
@@ -42,6 +34,14 @@ class DomPDF extends Core implements \PhpOffice\PhpSpreadsheet\Writer\IWriter
     public function __construct(\PhpOffice\PhpSpreadsheet\Spreadsheet $spreadsheet)
     {
         parent::__construct($spreadsheet);
+
+        /*  Require DomPDF library */
+        $pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/dompdf_config.inc.php';
+        if (file_exists($pdfRendererClassFile)) {
+            require_once $pdfRendererClassFile;
+        } else {
+            throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
+        }
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Writer/PDF/MPDF.php b/src/PhpSpreadsheet/Writer/PDF/MPDF.php
index 4d47903c..73abaa1b 100644
--- a/src/PhpSpreadsheet/Writer/PDF/MPDF.php
+++ b/src/PhpSpreadsheet/Writer/PDF/MPDF.php
@@ -2,14 +2,6 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
 
-/*  Require mPDF library */
-$pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/mpdf.php';
-if (file_exists($pdfRendererClassFile)) {
-    require_once $pdfRendererClassFile;
-} else {
-    throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
-}
-
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet
  *
@@ -42,6 +34,14 @@ class MPDF extends Core implements \PhpOffice\PhpSpreadsheet\Writer\IWriter
     public function __construct(\PhpOffice\PhpSpreadsheet\Spreadsheet $spreadsheet)
     {
         parent::__construct($spreadsheet);
+
+        /*  Require mPDF library */
+        $pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/mpdf.php';
+        if (file_exists($pdfRendererClassFile)) {
+            require_once $pdfRendererClassFile;
+        } else {
+            throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
+        }
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Writer/PDF/TcPDF.php b/src/PhpSpreadsheet/Writer/PDF/TcPDF.php
index c1be5abe..d3f4a41f 100644
--- a/src/PhpSpreadsheet/Writer/PDF/TcPDF.php
+++ b/src/PhpSpreadsheet/Writer/PDF/TcPDF.php
@@ -2,15 +2,6 @@
 
 namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
 
-/*  Require tcPDF library */
-$pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/tcpdf.php';
-if (file_exists($pdfRendererClassFile)) {
-    $k_path_url = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath();
-    require_once $pdfRendererClassFile;
-} else {
-    throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
-}
-
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet
  *
@@ -43,6 +34,15 @@ class TcPDF extends Core implements \PhpOffice\PhpSpreadsheet\Writer\IWriter
     public function __construct(\PhpOffice\PhpSpreadsheet\Spreadsheet $spreadsheet)
     {
         parent::__construct($spreadsheet);
+
+        /*  Require tcPDF library */
+        $pdfRendererClassFile = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath() . '/tcpdf.php';
+        if (file_exists($pdfRendererClassFile)) {
+            $k_path_url = \PhpOffice\PhpSpreadsheet\Settings::getPdfRendererPath();
+            require_once $pdfRendererClassFile;
+        } else {
+            throw new \PhpOffice\PhpSpreadsheet\Writer\Exception('Unable to load PDF Rendering library');
+        }
     }
 
     /**
diff --git a/tests/PhpSpreadsheetTests/Helper/MigratorTest.php b/tests/PhpSpreadsheetTests/Helper/MigratorTest.php
new file mode 100644
index 00000000..39a922ab
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Helper/MigratorTest.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Helper;
+
+use PhpOffice\PhpSpreadsheet\Helper\Migrator;
+
+class MigratorTest extends \PHPUnit_Framework_TestCase
+{
+    public function testMappingOnlyContainExistingClasses()
+    {
+        $migrator = new Migrator();
+
+        foreach ($migrator->getMapping() as $classname) {
+            if (substr_count($classname, '\\')) {
+                $this->assertTrue(class_exists($classname) || interface_exists($classname), 'mapping is wrong, class does not exists in project: ' . $classname);
+            }
+        }
+    }
+}