diff --git a/README.md b/README.md
index b8a9dc2..7755107 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ Click an image for the full size. All screenshots, with captions: [docs/images/s
 ## Requirements
 
 - phpBB 3.3.19 or later, including phpBB 4.0 (tested on its 4.0.0-a3 development version)
-- PHP 8.3.36 or later
+- PHP 8.1 or later
 
 ## Installation
 
diff --git a/composer.json b/composer.json
index ad1f4fb..4ddb171 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,7 @@
 		}
 	],
 	"require": {
-		"php": ">=8.3.36",
+		"php": ">=8.1.0",
 		"composer/installers": "^1.0 || ^2.0"
 	},
 	"extra": {
diff --git a/docs/design.md b/docs/design.md
index 3ea49fa..cf35da9 100644
--- a/docs/design.md
+++ b/docs/design.md
@@ -117,7 +117,7 @@ Config: `seenotes_label` (the label), `seenotes_require_description` (off) and `
 
 Other events: `core.permissions`, `core.delete_user_after`, `core.update_username`. No new phpBB events are needed.
 
-Same as the other phpbbmodders extensions: `ext.php` minimum version checks (phpBB 3.3.19, PHP 8.3.36), `extra.version-check` once a phpBB.com listing exists, the org's strict EPV workflow plus lint and tests, screen-reader text on icon-only controls, and language strings for everything shown.
+Same as the other phpbbmodders extensions: `ext.php` minimum version checks (phpBB 3.3.19, PHP 8.1), `extra.version-check` once a phpBB.com listing exists, the org's strict EPV workflow plus lint and tests, screen-reader text on icon-only controls, and language strings for everything shown.
 
 ## Privacy
 
diff --git a/ext.php b/ext.php
index f099110..180b835 100644
--- a/ext.php
+++ b/ext.php
@@ -49,12 +49,12 @@ public function check_phpbb_version()
 	}
 
 	/**
-	 * Requires PHP 8.3.36 due to security fixes.
+	 * Requires PHP 8.1.0 or later.
 	 *
 	 * @return bool
 	 */
 	public function check_php_version()
 	{
-		return PHP_VERSION_ID >= 80336;
+		return PHP_VERSION_ID >= 80100;
 	}
 }
diff --git a/language/en/install_seenotes.php b/language/en/install_seenotes.php
index eb808a0..09a28a0 100644
--- a/language/en/install_seenotes.php
+++ b/language/en/install_seenotes.php
@@ -22,7 +22,7 @@
 }
 
 $lang = array_merge($lang, [
-	'SEENOTES_NOT_ENABLEABLE'	=> 'See Notes could not be enabled. It needs phpBB 3.3.19 or later and PHP 8.3.36 or later.',
+	'SEENOTES_NOT_ENABLEABLE'	=> 'See Notes could not be enabled. It needs phpBB 3.3.19 or later and PHP 8.1 or later.',
 
 	// Starter reasons, added once when the extension is first enabled. They
 	// are stored in the board's default language and can then be edited in