diff --git a/.travis.yml b/.travis.yml
index 970fac0..6be4c18 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,12 @@
 language: go
 
 go:
-  - 1.6
-  - 1.7
-  - 1.8
   - 1.9
+  - 1.10.x
 
 before_install:
   - go get github.com/mattn/goveralls
-  - git clone https://github.com/jmcnamara/libxlsxwriter.git && cd libxlsxwriter && git checkout 79a9b41fd293dd4057b1fe43e3f8e13c7b242f6b && make && sudo INSTALL_DIR=/usr make install && cd .. && rm -rf libxlsxwriter
+  - git clone https://github.com/jmcnamara/libxlsxwriter.git && cd libxlsxwriter && make && sudo INSTALL_DIR=/usr make install && cd .. && rm -rf libxlsxwriter
 
 script:
-  - $HOME/gopath/bin/goveralls -service=travis-ci -ignore "examples/*/*.go"
+  - $HOME/gopath/bin/goveralls -service=travis-ci -ignore "examples/*/*.go" -v
diff --git a/format.go b/format.go
index 48aefaf..8d3d7b3 100644
--- a/format.go
+++ b/format.go
@@ -105,7 +105,7 @@ func (f *Format) SetFontName(fontName string) {
 
 // SetFontSize sets the font size.
 func (f *Format) SetFontSize(size int) {
-	cSize := (C.uint16_t)(size)
+	cSize := (C.double)(size)
 
 	C.format_set_font_size(f.CFormat, cSize)
 }