diff --git a/libweston/backend-drm/drm-gbm.c b/libweston/backend-drm/drm-gbm.c
index a24c7c31..ef3a123d 100644
--- a/libweston/backend-drm/drm-gbm.c
+++ b/libweston/backend-drm/drm-gbm.c
@@ -198,7 +198,6 @@ create_gbm_surface(struct gbm_device *gbm, struct drm_output *output)
 		return;
 	}
 
-#ifdef HAVE_GBM_MODIFIERS
 	if (!weston_drm_format_has_modifier(fmt, DRM_FORMAT_MOD_INVALID)) {
 		modifiers = weston_drm_format_get_modifiers(fmt, &num_modifiers);
 		output->gbm_surface =
@@ -207,7 +206,6 @@ create_gbm_surface(struct gbm_device *gbm, struct drm_output *output)
 							  output->format->format,
 							  modifiers, num_modifiers);
 	}
-#endif
 
 	/*
 	 * If we cannot use modifiers to allocate the GBM surface and the GBM
@@ -220,9 +218,8 @@ create_gbm_surface(struct gbm_device *gbm, struct drm_output *output)
 
 	/* We may allocate with no modifiers in the following situations:
 	 *
-	 * 1. old GBM version, so HAVE_GBM_MODIFIERS is false;
-	 * 2. the KMS driver does not support modifiers;
-	 * 3. if allocating with modifiers failed, what can happen when the KMS
+	 * 1. the KMS driver does not support modifiers;
+	 * 2. if allocating with modifiers failed, what can happen when the KMS
 	 *    display device supports modifiers but the GBM driver does not,
 	 *    e.g. the old i915 Mesa driver.
 	 */
diff --git a/libweston/backend-drm/fb.c b/libweston/backend-drm/fb.c
index 92041778..8c200b88 100644
--- a/libweston/backend-drm/fb.c
+++ b/libweston/backend-drm/fb.c
@@ -376,12 +376,6 @@ drm_fb_get_from_dmabuf(struct linux_dmabuf_buffer *dmabuf,
 		       struct drm_device *device, bool is_opaque,
 		       uint32_t *try_view_on_plane_failure_reasons)
 {
-#ifndef HAVE_GBM_FD_IMPORT
-	/* Importing a buffer to KMS requires explicit modifiers, so
-	 * we can't continue with the legacy GBM_BO_IMPORT_FD instead
-	 * of GBM_BO_IMPORT_FD_MODIFIER. */
-	return NULL;
-#else
 	struct drm_backend *backend = device->backend;
 	struct drm_fb *fb;
 	int i;
@@ -492,7 +486,6 @@ drm_fb_get_from_dmabuf(struct linux_dmabuf_buffer *dmabuf,
 err_free:
 	drm_fb_destroy_dmabuf(fb);
 	return NULL;
-#endif
 }
 
 struct drm_fb *
@@ -500,9 +493,7 @@ drm_fb_get_from_bo(struct gbm_bo *bo, struct drm_device *device,
 		   bool is_opaque, enum drm_fb_type type)
 {
 	struct drm_fb *fb = gbm_bo_get_user_data(bo);
-#ifdef HAVE_GBM_MODIFIERS
 	int i;
-#endif
 
 	if (fb) {
 		assert(fb->type == type);
@@ -524,7 +515,6 @@ drm_fb_get_from_bo(struct gbm_bo *bo, struct drm_device *device,
 	fb->format = pixel_format_get_info(gbm_bo_get_format(bo));
 	fb->size = 0;
 
-#ifdef HAVE_GBM_MODIFIERS
 	fb->modifier = gbm_bo_get_modifier(bo);
 	fb->num_planes = gbm_bo_get_plane_count(bo);
 	for (i = 0; i < fb->num_planes; i++) {
@@ -532,12 +522,6 @@ drm_fb_get_from_bo(struct gbm_bo *bo, struct drm_device *device,
 		fb->handles[i] = gbm_bo_get_handle_for_plane(bo, i).u32;
 		fb->offsets[i] = gbm_bo_get_offset(bo, i);
 	}
-#else
-	fb->num_planes = 1;
-	fb->strides[0] = gbm_bo_get_stride(bo);
-	fb->handles[0] = gbm_bo_get_handle(bo).u32;
-	fb->modifier = DRM_FORMAT_MOD_INVALID;
-#endif
 
 	if (!fb->format) {
 		weston_log("couldn't look up format 0x%lx\n",
diff --git a/libweston/backend-drm/meson.build b/libweston/backend-drm/meson.build
index 1af628d6..e048789b 100644
--- a/libweston/backend-drm/meson.build
+++ b/libweston/backend-drm/meson.build
@@ -62,12 +62,6 @@ if get_option('renderer-gl')
 	if not dep_gbm.found()
 		error('drm-backend with GL renderer requires gbm which was not found. Or, you can use \'-Drenderer-gl=false\'.')
 	endif
-	if dep_gbm.version().version_compare('>= 17.1')
-		config_h.set('HAVE_GBM_MODIFIERS', '1')
-	endif
-	if dep_gbm.version().version_compare('>= 17.2')
-		config_h.set('HAVE_GBM_FD_IMPORT', '1')
-	endif
 	deps_drm += dep_gbm
 	srcs_drm += 'drm-gbm.c'
 	config_h.set('BUILD_DRM_GBM', '1')