minor changes
diff --git a/DESCRIPTION b/DESCRIPTION
index 2b700da..bfa640d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -26,7 +26,7 @@
 Depends:
     R (>= 3.1.0)
 Imports:
-    knitr (>= 1.13),
+    knitr (>= 1.16),
     magrittr,
     stringr (>= 1.0),
     xml2,
diff --git a/docs/use_kableExtra_with_formattable.Rmd b/docs/use_kableExtra_with_formattable.Rmd
index e19dd2f..14f2ea8 100644
--- a/docs/use_kableExtra_with_formattable.Rmd
+++ b/docs/use_kableExtra_with_formattable.Rmd
@@ -3,6 +3,10 @@
 author: "Hao Zhu"
 date: "`r Sys.Date()`"
 output: html_document
+vignette: >
+  %\VignetteIndexEntry{Use kableExtra with formattable}
+  %\VignetteEngine{knitr::rmarkdown}
+  %\VignetteEncoding{UTF-8}
 ---
 
 I know you love `formattable`'s `color_tile` and `color_bar`. I do too. In my mind, these two features are among the best visualization methods in a tabular format. You may wonder if it's possible use it together with `kableExtra` so you can have a nested table with awesome presentation at the same time. Here is how. 
diff --git a/vignettes/use_kableExtra_with_formattable.Rmd b/vignettes/use_kableExtra_with_formattable.Rmd
index e19dd2f..14f2ea8 100644
--- a/vignettes/use_kableExtra_with_formattable.Rmd
+++ b/vignettes/use_kableExtra_with_formattable.Rmd
@@ -3,6 +3,10 @@
 author: "Hao Zhu"
 date: "`r Sys.Date()`"
 output: html_document
+vignette: >
+  %\VignetteIndexEntry{Use kableExtra with formattable}
+  %\VignetteEngine{knitr::rmarkdown}
+  %\VignetteEncoding{UTF-8}
 ---
 
 I know you love `formattable`'s `color_tile` and `color_bar`. I do too. In my mind, these two features are among the best visualization methods in a tabular format. You may wonder if it's possible use it together with `kableExtra` so you can have a nested table with awesome presentation at the same time. Here is how.