diff --git a/MCUFRIEND_kbv.cpp b/MCUFRIEND_kbv.cpp
index 66ad08e..d0700cd 100644
--- a/MCUFRIEND_kbv.cpp
+++ b/MCUFRIEND_kbv.cpp
@@ -796,7 +796,7 @@ void MCUFRIEND_kbv::vertScroll(int16_t top, int16_t scrollines, int16_t offset)
     }
 }
 
-void MCUFRIEND_kbv::invertDisplay(boolean i)
+void MCUFRIEND_kbv::invertDisplay(bool i)
 {
     uint8_t val;
     _lcd_rev = ((_lcd_capable & REV_SCREEN) != 0) ^ i;
diff --git a/MCUFRIEND_kbv.h b/MCUFRIEND_kbv.h
index db142b8..4030708 100644
--- a/MCUFRIEND_kbv.h
+++ b/MCUFRIEND_kbv.h
@@ -33,7 +33,7 @@ class MCUFRIEND_kbv : public Adafruit_GFX {
 	virtual void     drawFastHLine(int16_t x, int16_t y, int16_t w, uint16_t color) { fillRect(x, y, w, 1, color); }
 	virtual void     fillScreen(uint16_t color)                                     { fillRect(0, 0, _width, _height, color); }
 	virtual void     setRotation(uint8_t r);
-    virtual void     invertDisplay(boolean i);
+    virtual void     invertDisplay(bool i);
 
 	uint16_t readReg(uint16_t reg, int8_t index=0);
 	int16_t  readGRAM(int16_t x, int16_t y, uint16_t *block, int16_t w, int16_t h);
diff --git a/OPENSMART_kbv.h b/OPENSMART_kbv.h
index 543cba3..9b44faa 100644
--- a/OPENSMART_kbv.h
+++ b/OPENSMART_kbv.h
@@ -34,7 +34,7 @@ class OPENSMART_kbv : public Adafruit_GFX {
 	virtual void     drawFastHLine(int16_t x, int16_t y, int16_t w, uint16_t color) { fillRect(x, y, w, 1, color); }
 	virtual void     fillScreen(uint16_t color)                                     { fillRect(0, 0, _width, _height, color); }
 	virtual void     setRotation(uint8_t r);
-    virtual void     invertDisplay(boolean i);
+    virtual void     invertDisplay(bool i);
 
 	uint16_t readReg(uint16_t reg, int8_t index=0);
 	int16_t  readGRAM(int16_t x, int16_t y, uint16_t *block, int16_t w, int16_t h);