diff --git a/lib/carbon/platform.h b/lib/carbon/platform.h
index fd4ea658..389c6f04 100644
--- a/lib/carbon/platform.h
+++ b/lib/carbon/platform.h
@@ -177,8 +177,6 @@ struct _GLFWwin_struct {
     int       samples;
 
     // OpenGL extensions and context attributes
-    int       has_GL_SGIS_generate_mipmap;
-    int       has_GL_ARB_texture_non_power_of_two;
     int       glMajor, glMinor, glRevision;
     int       glForward, glDebug, glProfile;
 
diff --git a/lib/cocoa/platform.h b/lib/cocoa/platform.h
index f1e97f7a..b8571b7a 100644
--- a/lib/cocoa/platform.h
+++ b/lib/cocoa/platform.h
@@ -109,8 +109,6 @@ struct _GLFWwin_struct {
     int       samples;
 
     // OpenGL extensions and context attributes
-    int       has_GL_SGIS_generate_mipmap;
-    int       has_GL_ARB_texture_non_power_of_two;
     int       glMajor, glMinor, glRevision;
     int       glForward, glDebug, glProfile;
 
diff --git a/lib/win32/platform.h b/lib/win32/platform.h
index 0d3e702f..682de181 100644
--- a/lib/win32/platform.h
+++ b/lib/win32/platform.h
@@ -321,8 +321,6 @@ struct _GLFWwin_struct {
     int       samples;
 
     // OpenGL extensions and context attributes
-    int       has_GL_SGIS_generate_mipmap;
-    int       has_GL_ARB_texture_non_power_of_two;
     int       glMajor, glMinor, glRevision;
     int       glForward, glDebug, glProfile;
 
diff --git a/lib/window.c b/lib/window.c
index fc4a0203..6e4b6a59 100644
--- a/lib/window.c
+++ b/lib/window.c
@@ -530,16 +530,6 @@ GLFWAPI int glfwOpenWindow(int width, int height,
         return GL_FALSE;
     }
 
-    // Do we have non-power-of-two textures (added to core in version 2.0)?
-    _glfwWin.has_GL_ARB_texture_non_power_of_two =
-        (_glfwWin.glMajor >= 2) ||
-        glfwExtensionSupported("GL_ARB_texture_non_power_of_two");
-
-    // Do we have automatic mipmap generation (added to core in version 1.4)?
-    _glfwWin.has_GL_SGIS_generate_mipmap =
-        (_glfwWin.glMajor >= 2) || (_glfwWin.glMinor >= 4) ||
-        glfwExtensionSupported("GL_SGIS_generate_mipmap");
-
     if (_glfwWin.glMajor > 2)
     {
         _glfwWin.GetStringi = (PFNGLGETSTRINGIPROC) glfwGetProcAddress("glGetStringi");
diff --git a/lib/x11/platform.h b/lib/x11/platform.h
index 39a90fc6..51efecef 100644
--- a/lib/x11/platform.h
+++ b/lib/x11/platform.h
@@ -204,8 +204,6 @@ struct _GLFWwin_struct {
     int       samples;
 
     // OpenGL extensions and context attributes
-    int       has_GL_SGIS_generate_mipmap;
-    int       has_GL_ARB_texture_non_power_of_two;
     int       glMajor, glMinor, glRevision;
     int       glForward, glDebug, glProfile;