diff --git a/compton.sample.conf b/compton.sample.conf
index 52975f5..ca655dc 100644
--- a/compton.sample.conf
+++ b/compton.sample.conf
@@ -71,7 +71,6 @@ invert-color-include = [ ];
 # glx-no-stencil = true;
 # glx-no-rebind-pixmap = true;
 glx-swap-method = "undefined";
-# glx-use-gpushader4 = true;
 # xrender-sync = true;
 # xrender-sync-fence = true;
 
diff --git a/man/compton.1.asciidoc b/man/compton.1.asciidoc
index 9f78e40..00e259b 100644
--- a/man/compton.1.asciidoc
+++ b/man/compton.1.asciidoc
@@ -249,9 +249,6 @@ May also be one of the predefined kernels: `3x3box` (default), `5x5box`, `7x7box
 *--glx-swap-method* undefined/exchange/copy/3/4/5/6/buffer-age::
 	GLX backend: GLX buffer swap method we assume. Could be `undefined` (0), `copy` (1), `exchange` (2), 3-6, or `buffer-age` (-1).  `undefined` is the slowest and the safest, and the default value. `copy` is fastest, but may fail on some drivers, 2-6 are gradually slower but safer (6 is still faster than 0). Usually, double buffer means 2, triple buffer means 3. `buffer-age` means auto-detect using 'GLX_EXT_buffer_age', supported by some drivers. Partially breaks `--resize-damage`. Defaults to `undefined`.
 
-*--glx-use-gpushader4*::
-	GLX backend: Use 'GL_EXT_gpu_shader4' for some optimization on blur GLSL code. My tests on GTX 670 show no noticeable effect.
-
 *--xrender-sync-fence*::
 	Use X Sync fence to sync clients' draw calls, to make sure all draw calls are finished before compton starts drawing. Needed on nvidia-drivers with GLX backend for some users.
 
diff --git a/src/config.h b/src/config.h
index 00e95f6..3c31d21 100644
--- a/src/config.h
+++ b/src/config.h
@@ -95,8 +95,6 @@ typedef struct options_t {
 	bool glx_no_rebind_pixmap;
 	/// GLX swap method we assume OpenGL uses.
 	int glx_swap_method;
-	/// Whether to use GL_EXT_gpu_shader4 to (hopefully) accelerates blurring.
-	bool glx_use_gpushader4;
 	/// Custom fragment shader for painting windows, as a string.
 	char *glx_fshader_win_str;
 	/// Whether to detect rounded corners.
diff --git a/src/config_libconfig.c b/src/config_libconfig.c
index 829b1ee..dae94b7 100644
--- a/src/config_libconfig.c
+++ b/src/config_libconfig.c
@@ -398,7 +398,10 @@ char *parse_config_libconfig(options_t *opt, const char *config_file, bool *shad
     }
   }
   // --glx-use-gpushader4
-  lcfg_lookup_bool(&cfg, "glx-use-gpushader4", &opt->glx_use_gpushader4);
+  if (config_lookup_bool(&cfg, "glx-use-gpushader4", &ival) && ival) {
+    log_warn("glx-use-gpushader4 is deprecated since v6, please remove it from"
+             "your config file");
+  }
   // --xrender-sync
   if (config_lookup_bool(&cfg, "xrender-sync", &ival) && ival) {
     log_warn("Please use xrender-sync-fence instead of xrender-sync.");
diff --git a/src/opengl.c b/src/opengl.c
index 00b9f5a..6561280 100644
--- a/src/opengl.c
+++ b/src/opengl.c
@@ -310,8 +310,6 @@ glx_init_blur(session_t *ps) {
       "  vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);\n";
     static const char *FRAG_SHADER_BLUR_ADD =
       "  sum += float(%.7g) * %s(tex_scr, vec2(gl_TexCoord[0].x + offset_x * float(%d), gl_TexCoord[0].y + offset_y * float(%d)));\n";
-    static const char *FRAG_SHADER_BLUR_ADD_GPUSHADER4 =
-      "  sum += float(%.7g) * %sOffset(tex_scr, vec2(gl_TexCoord[0].x, gl_TexCoord[0].y), ivec2(%d, %d));\n";
     static const char *FRAG_SHADER_BLUR_SUFFIX =
       "  sum += %s(tex_scr, vec2(gl_TexCoord[0].x, gl_TexCoord[0].y)) * factor_center;\n"
       "  gl_FragColor = sum / (factor_center + float(%.7g));\n"
@@ -327,10 +325,6 @@ glx_init_blur(session_t *ps) {
     if (use_texture_rect) {
       mstrextend(&extension, "#extension GL_ARB_texture_rectangle : require\n");
     }
-    if (ps->o.glx_use_gpushader4) {
-      mstrextend(&extension, "#extension GL_EXT_gpu_shader4 : require\n");
-      shader_add = FRAG_SHADER_BLUR_ADD_GPUSHADER4;
-    }
     if (!extension) {
       extension = strdup("");
     }
@@ -402,10 +396,8 @@ glx_init_blur(session_t *ps) {
     }
 
       P_GET_UNIFM_LOC("factor_center", unifm_factor_center);
-      if (!ps->o.glx_use_gpushader4) {
-        P_GET_UNIFM_LOC("offset_x", unifm_offset_x);
-        P_GET_UNIFM_LOC("offset_y", unifm_offset_y);
-      }
+      P_GET_UNIFM_LOC("offset_x", unifm_offset_x);
+      P_GET_UNIFM_LOC("offset_y", unifm_offset_y);
 
 #undef P_GET_UNIFM_LOC
     }
diff --git a/src/options.c b/src/options.c
index 12ef712..d570f94 100644
--- a/src/options.c
+++ b/src/options.c
@@ -715,7 +715,11 @@ void get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 				exit(1);
 			break;
 		P_CASELONG(302, resize_damage);
-		P_CASEBOOL(303, glx_use_gpushader4);
+		case 303:
+			// --glx-use-gpushader4
+			log_warn("--glx-use-gpushader4 is deprecated since v6."
+			         " Please remove it from command line options.");
+			break;
 		case 304:
 			// --opacity-rule
 			if (!parse_rule_opacity(&opt->opacity_rules, optarg))
@@ -816,7 +820,8 @@ void get_cfg(options_t *opt, int argc, char *const *argv, bool shadow_enable,
 
 	// Fill default blur kernel
 	if (opt->blur_background && !opt->blur_kerns[0]) {
-		CHECK(parse_blur_kern_lst("3x3box", opt->blur_kerns, MAX_BLUR_PASS, &conv_kern_hasneg));
+		CHECK(parse_blur_kern_lst("3x3box", opt->blur_kerns, MAX_BLUR_PASS,
+		                          &conv_kern_hasneg));
 	}
 
 	if (opt->resize_damage < 0) {