diff --git a/scripts/sphinx-pre-install b/scripts/sphinx-pre-install
index 249edb3..0d5684c 100755
--- a/scripts/sphinx-pre-install
+++ b/scripts/sphinx-pre-install
@@ -29,6 +29,8 @@
 my $virtenv_dir = "";
 my $python_cmd = "";
 my $min_version;
+my $rec_version = "1.7.9";	# PDF won't build here
+my $min_pdf_version = "2.4.4";	# Min version where pdf builds
 
 #
 # Command line arguments
@@ -254,7 +256,7 @@
 
 sub check_sphinx()
 {
-	my $rec_version;
+	my $default_version;
 	my $cur_version;
 
 	open IN, $conf or die "Can't open $conf";
@@ -271,15 +273,15 @@
 	open IN, $requirement_file or die "Can't open $requirement_file";
 	while (<IN>) {
 		if (m/^\s*Sphinx\s*==\s*([\d\.]+)$/) {
-			$rec_version=$1;
+			$default_version=$1;
 			last;
 		}
 	}
 	close IN;
 
-	die "Can't get recommended sphinx version from $requirement_file" if (!$min_version);
+	die "Can't get default sphinx version from $requirement_file" if (!$default_version);
 
-	$virtenv_dir = $virtenv_prefix . $rec_version;
+	$virtenv_dir = $virtenv_prefix . $default_version;
 
 	my $sphinx = get_sphinx_fname();
 	if ($sphinx eq "") {
@@ -294,7 +296,7 @@
 
 	if ($cur_version lt $min_version) {
 		printf "ERROR: Sphinx version is %s. It should be >= %s (recommended >= %s)\n",
-		       $cur_version, $min_version, $rec_version;;
+		       $cur_version, $min_version, $default_version;
 		$need_sphinx = 1;
 		return;
 	}
@@ -302,6 +304,13 @@
 	if ($cur_version lt $rec_version) {
 		printf "Sphinx version %s\n", $cur_version;
 		print "Warning: It is recommended at least Sphinx version $rec_version.\n";
+		print "         If you want pdf, you need at least $min_pdf_version.\n";
+		$rec_sphinx_upgrade = 1;
+		return;
+	}
+	if ($cur_version lt $min_pdf_version) {
+		printf "Sphinx version %s\n", $cur_version;
+		print "Note: It is recommended at least Sphinx version $min_pdf_version if you need PDF support.\n";
 		$rec_sphinx_upgrade = 1;
 		return;
 	}