diff --git a/.travis.yml b/.travis.yml
index 9f892c5..faf9916 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@ install:
   - go get -d -t -v ./... && go build -v ./...
 
 go:
-  - 1.9.x
   - 1.10.x
   - 1.11.x
   - 1.12.x
diff --git a/adjust.go b/adjust.go
index ccc5ce9..186112d 100644
--- a/adjust.go
+++ b/adjust.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/calcchain.go b/calcchain.go
index ce679e5..b4cadef 100644
--- a/calcchain.go
+++ b/calcchain.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/cell.go b/cell.go
index 6743e2a..f61e268 100644
--- a/cell.go
+++ b/cell.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/cellmerged.go b/cellmerged.go
index a78b244..c1df9b3 100644
--- a/cellmerged.go
+++ b/cellmerged.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/chart.go b/chart.go
index b9439ca..6a106f0 100644
--- a/chart.go
+++ b/chart.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/col.go b/col.go
index db3a901..ffa0ca6 100644
--- a/col.go
+++ b/col.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/comment.go b/comment.go
index bc6fa27..97e0e9b 100644
--- a/comment.go
+++ b/comment.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/datavalidation.go b/datavalidation.go
index 209204a..2499035 100644
--- a/datavalidation.go
+++ b/datavalidation.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/datavalidation_test.go b/datavalidation_test.go
index 0fee092..211830d 100644
--- a/datavalidation_test.go
+++ b/datavalidation_test.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/date.go b/date.go
index b49a695..8f63702 100644
--- a/date.go
+++ b/date.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/docProps.go b/docProps.go
index ff19fda..166512f 100644
--- a/docProps.go
+++ b/docProps.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/docProps_test.go b/docProps_test.go
index 1f52beb..671d998 100644
--- a/docProps_test.go
+++ b/docProps_test.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/errors.go b/errors.go
index 3404c7e..8520a01 100644
--- a/errors.go
+++ b/errors.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/excelize.go b/excelize.go
index 6d014a0..b734e57 100644
--- a/excelize.go
+++ b/excelize.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 //
 // See https://xuri.me/excelize for more information about this package.
 package excelize
diff --git a/file.go b/file.go
index a4aa11d..46f1f62 100644
--- a/file.go
+++ b/file.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/lib.go b/lib.go
index b99b175..4dea16a 100644
--- a/lib.go
+++ b/lib.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/picture.go b/picture.go
index 812eb5c..62d48dc 100644
--- a/picture.go
+++ b/picture.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/rows.go b/rows.go
index c17179f..6281e62 100644
--- a/rows.go
+++ b/rows.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/shape.go b/shape.go
index 7dc7021..e3ed968 100644
--- a/shape.go
+++ b/shape.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/sheet.go b/sheet.go
index 935deac..ed6d888 100644
--- a/sheet.go
+++ b/sheet.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
@@ -740,9 +740,7 @@ func (f *File) searchSheet(name, value string, regSearch bool) ([]string, error)
 		result    []string
 		r         xlsxRow
 	)
-	xml.NewDecoder(bytes.NewReader(f.readXML(name)))
 	d := f.sharedStringsReader()
-
 	decoder := xml.NewDecoder(bytes.NewReader(f.readXML(name)))
 	for {
 		token, _ := decoder.Token()
diff --git a/sheetpr.go b/sheetpr.go
index 66761f3..a273ac1 100644
--- a/sheetpr.go
+++ b/sheetpr.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/sheetview.go b/sheetview.go
index 9712d85..09f5789 100644
--- a/sheetview.go
+++ b/sheetview.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/sparkline.go b/sparkline.go
index 73e125e..18eae6c 100644
--- a/sparkline.go
+++ b/sparkline.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/styles.go b/styles.go
index 04a5c33..c19cee0 100644
--- a/styles.go
+++ b/styles.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/table.go b/table.go
index 3d8d402..45a1622 100644
--- a/table.go
+++ b/table.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/templates.go b/templates.go
index 923cebd..0d3a0c5 100644
--- a/templates.go
+++ b/templates.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 //
 // This file contains default templates for XML files we don't yet populated
 // based on content.
diff --git a/test/SharedStrings.xlsx b/test/SharedStrings.xlsx
index d6004c0..bcea2c8 100644
Binary files a/test/SharedStrings.xlsx and b/test/SharedStrings.xlsx differ
diff --git a/vmlDrawing.go b/vmlDrawing.go
index 8b1d00f..24b615f 100644
--- a/vmlDrawing.go
+++ b/vmlDrawing.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlApp.go b/xmlApp.go
index ad414fa..48450e3 100644
--- a/xmlApp.go
+++ b/xmlApp.go
@@ -5,12 +5,15 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
 import "encoding/xml"
 
+// xlsxProperties specifies to an OOXML document properties such as the
+// template used, the number of pages and words, and the application name and
+// version.
 type xlsxProperties struct {
 	XMLName              xml.Name `xml:"http://schemas.openxmlformats.org/officeDocument/2006/extended-properties Properties"`
 	Template             string
@@ -42,6 +45,8 @@ type xlsxProperties struct {
 	DocSecurity          int
 }
 
+// xlsxVectorVariant specifies the set of hyperlinks that were in this
+// document when last saved.
 type xlsxVectorVariant struct {
 	Content string `xml:",innerxml"`
 }
@@ -50,6 +55,7 @@ type xlsxVectorLpstr struct {
 	Content string `xml:",innerxml"`
 }
 
+// xlsxDigSig contains the signature of a digitally signed document.
 type xlsxDigSig struct {
 	Content string `xml:",innerxml"`
 }
diff --git a/xmlCalcChain.go b/xmlCalcChain.go
index 05a176d..343f15f 100644
--- a/xmlCalcChain.go
+++ b/xmlCalcChain.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlChart.go b/xmlChart.go
index 8a3a680..bb4b4bc 100644
--- a/xmlChart.go
+++ b/xmlChart.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlComments.go b/xmlComments.go
index 47d8f51..f13d002 100644
--- a/xmlComments.go
+++ b/xmlComments.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlContentTypes.go b/xmlContentTypes.go
index e99b0b3..fa4d347 100644
--- a/xmlContentTypes.go
+++ b/xmlContentTypes.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlCore.go b/xmlCore.go
index 357f688..96482fc 100644
--- a/xmlCore.go
+++ b/xmlCore.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlDecodeDrawing.go b/xmlDecodeDrawing.go
index 6cb224a..e11bb00 100644
--- a/xmlDecodeDrawing.go
+++ b/xmlDecodeDrawing.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlDrawing.go b/xmlDrawing.go
index 20cb83d..ade6261 100644
--- a/xmlDrawing.go
+++ b/xmlDrawing.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlSharedStrings.go b/xmlSharedStrings.go
index 48d4464..7983741 100644
--- a/xmlSharedStrings.go
+++ b/xmlSharedStrings.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlStyles.go b/xmlStyles.go
index 49abe3c..5823bc9 100644
--- a/xmlStyles.go
+++ b/xmlStyles.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlTable.go b/xmlTable.go
index 6d27dc9..ca4ce03 100644
--- a/xmlTable.go
+++ b/xmlTable.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlTheme.go b/xmlTheme.go
index 01d0054..f764c20 100644
--- a/xmlTheme.go
+++ b/xmlTheme.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlWorkbook.go b/xmlWorkbook.go
index 0118685..8150e29 100644
--- a/xmlWorkbook.go
+++ b/xmlWorkbook.go
@@ -5,7 +5,7 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
diff --git a/xmlWorksheet.go b/xmlWorksheet.go
index a5db776..09dec5e 100644
--- a/xmlWorksheet.go
+++ b/xmlWorksheet.go
@@ -5,13 +5,11 @@
 // Package excelize providing a set of functions that allow you to write to
 // and read from XLSX files. Support reads and writes XLSX file generated by
 // Microsoft Excel™ 2007 and later. Support save file without losing original
-// charts of XLSX. This library needs Go version 1.8 or later.
+// charts of XLSX. This library needs Go version 1.10 or later.
 
 package excelize
 
-import (
-	"encoding/xml"
-)
+import "encoding/xml"
 
 // xlsxWorksheet directly maps the worksheet element in the namespace
 // http://schemas.openxmlformats.org/spreadsheetml/2006/main - currently I have