diff --git a/R/add_header_above.R b/R/add_header_above.R
index bf99378..72fac20 100644
--- a/R/add_header_above.R
+++ b/R/add_header_above.R
@@ -28,8 +28,10 @@
                              monospace = FALSE, escape = TRUE) {
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    stop("Please specify output format in your kable function. Currently ",
-         "generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+         "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+         "for details.")
+    return(kable_input)
   }
   if (kable_format == "html") {
     return(htmlTable_add_header_above(kable_input, header,
diff --git a/R/add_indent.R b/R/add_indent.R
index 8dc2d4d..886fc1c 100644
--- a/R/add_indent.R
+++ b/R/add_indent.R
@@ -15,7 +15,9 @@
   }
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {
diff --git a/R/collapse_rows.R b/R/collapse_rows.R
index 1f9d0d3..9feb93d 100644
--- a/R/collapse_rows.R
+++ b/R/collapse_rows.R
@@ -23,7 +23,9 @@
   # }
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {
diff --git a/R/column_spec.R b/R/column_spec.R
index da8252c..bdd8b2b 100644
--- a/R/column_spec.R
+++ b/R/column_spec.R
@@ -45,7 +45,9 @@
   }
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {
diff --git a/R/footnote.R b/R/footnote.R
index bb48e0d..066e96f 100644
--- a/R/footnote.R
+++ b/R/footnote.R
@@ -51,7 +51,9 @@
 ) {
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (length(alphabet) > 26) {
diff --git a/R/group_rows.R b/R/group_rows.R
index 7009995..7300eb3 100644
--- a/R/group_rows.R
+++ b/R/group_rows.R
@@ -34,7 +34,9 @@
 
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (is.null(index)) {
diff --git a/R/kable_styling.R b/R/kable_styling.R
index d349120..305d3d0 100644
--- a/R/kable_styling.R
+++ b/R/kable_styling.R
@@ -79,8 +79,10 @@
   kable_format <- attr(kable_input, "format")
 
   if (!kable_format %in% c("html", "latex")) {
-      message("Currently generic markdown table using pandoc is not supported.")
-      return(kable_input)
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
+    return(kable_input)
   }
   if (kable_format == "html") {
     if (is.null(full_width)) {
diff --git a/R/landscape.R b/R/landscape.R
index 01ef2bb..d7b3cd1 100644
--- a/R/landscape.R
+++ b/R/landscape.R
@@ -13,7 +13,9 @@
 landscape <- function(kable_input, margin = NULL) {
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {
diff --git a/R/row_spec.R b/R/row_spec.R
index ee27be7..0d3d74a 100644
--- a/R/row_spec.R
+++ b/R/row_spec.R
@@ -49,7 +49,9 @@
   }
   kable_format <- attr(kable_input, "format")
   if (!kable_format %in% c("html", "latex")) {
-    message("Currently generic markdown table using pandoc is not supported.")
+    warning("Please specify format in kable. kableExtra can customize either ",
+            "HTML or LaTeX outputs. See https://haozhu233.github.io/kableExtra/ ",
+            "for details.")
     return(kable_input)
   }
   if (kable_format == "html") {