diff --git a/CHANGELOG.md b/CHANGELOG.md
index 922a5183..01b65cd3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,11 +3,12 @@
 ## Unreleased
 
 - Require WordPress 4.6 or newer
-- Load text-domain on-demand
-- Call `redis_object_cache_error` action before `wp_die()`
-- Don't try to define `WP_REDIS_PLUGIN_PATH` twice
+- Load text-domain only when needed
+- Added `WP_REDIS_DISABLE_DROPIN_CHECK` constant
 - Respect `file_mod_allowed` filter and `DISALLOW_FILE_MODS` constant
 - Renamed `.redis-write-test.tmp` test file to `object-cache.tmp`
+- Call `redis_object_cache_error` action before `wp_die()`
+- Allow `WP_REDIS_PLUGIN_PATH` to be defined elsewhere
 
 ## 2.4.4
 
diff --git a/README.md b/README.md
index 25d34383..20594f70 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@ The Redis Object Cache plugin comes with vast set of configuration options. If y
 | `WP_REDIS_DISABLE_ADMINBAR`          | `false`     | Disables admin bar display |
 | `WP_REDIS_DISABLE_METRICS`           | `false`     | Disables metrics collection and display |
 | `WP_REDIS_DISABLE_BANNERS`           | `false`     | Disables promotional banners |
+| `WP_REDIS_DISABLE_DROPIN_CHECK`      | `false`     | Disables the extended drop-in write test |
 | `WP_REDIS_DISABLE_DROPIN_AUTOUPDATE` | `false`     | Disables the drop-in auto-update |
 | `WP_REDIS_SSL_CONTEXT`               | `[]`        | TLS connection options for `tls` or `rediss` scheme |
 
diff --git a/includes/class-plugin.php b/includes/class-plugin.php
index 05a3cba5..047d980c 100644
--- a/includes/class-plugin.php
+++ b/includes/class-plugin.php
@@ -1391,6 +1391,20 @@ public function test_filesystem_writing() {
             return new WP_Error( 'fs', __( 'Could not initialize filesystem.', 'redis-cache' ) );
         }
 
+        $dropin_check = ! defined( 'WP_REDIS_DISABLE_DROPIN_CHECK' ) || ! WP_REDIS_DISABLE_DROPIN_CHECK;
+
+        if ( ! $dropin_check ) {
+            if ( ! $wp_filesystem->exists( WP_CONTENT_DIR . '/object-cache.php' ) ) {
+                return true;
+            }
+
+            if ( ! $wp_filesystem->is_writable( WP_CONTENT_DIR . '/object-cache.php' ) ) {
+                return new WP_Error( 'writable', __( 'Object cache drop-in is not writable.', 'redis-cache' ) );
+            }
+
+            return true;
+        }
+
         $cachefile = WP_REDIS_PLUGIN_PATH . '/includes/object-cache.php';
         $testfile = WP_CONTENT_DIR . '/object-cache.tmp';
 
@@ -1405,7 +1419,7 @@ public function test_filesystem_writing() {
         }
 
         if ( ! $wp_filesystem->is_writable( WP_CONTENT_DIR ) ) {
-            return new WP_Error( 'copy', __( 'Content directory is not writable.', 'redis-cache' ) );
+            return new WP_Error( 'writable', __( 'Content directory is not writable.', 'redis-cache' ) );
         }
 
         if ( ! $wp_filesystem->copy( $cachefile, $testfile, true, FS_CHMOD_FILE ) ) {