diff --git a/includes/class-freemius.php b/includes/class-freemius.php
index 6fc8bd9a..f4249b8f 100755
--- a/includes/class-freemius.php
+++ b/includes/class-freemius.php
@@ -19869,8 +19869,15 @@ private function _store_plans( $store = true ) {
 
             // Copy plans.
             $encrypted_plans = array();
-            for ( $i = 0, $len = count( $this->_plans ); $i < $len; $i ++ ) {
-                $encrypted_plans[] = self::_encrypt_entity( $this->_plans[ $i ] );
+
+            // `_plans` defaults to `false` and is only assigned once the account carries a plan
+            // list (`_set_account()` skips the assignment when `$plans === false`). On a fresh
+            // first opt-in of a product without paid plans it can therefore still be `false` here,
+            // and `count( false )` is a fatal TypeError on PHP 8. Treat a missing list as empty.
+            $plans_to_encrypt = is_array( $this->_plans ) ? $this->_plans : array();
+
+            for ( $i = 0, $len = count( $plans_to_encrypt ); $i < $len; $i ++ ) {
+                $encrypted_plans[] = self::_encrypt_entity( $plans_to_encrypt[ $i ] );
             }
 
             $plans[ $this->_slug ] = $encrypted_plans;
diff --git a/includes/entities/class-fs-site.php b/includes/entities/class-fs-site.php
index 9b35f328..c167d7d4 100755
--- a/includes/entities/class-fs-site.php
+++ b/includes/entities/class-fs-site.php
@@ -120,7 +120,10 @@ function __construct( $site = false ) {
             parent::__construct( $site );
 
             if ( is_object( $site ) ) {
-                $this->plan_id = $site->plan_id;
+                // The install payload can arrive without `plan_id` (e.g. a fresh/new-user
+                // connection of a product without paid plans), which raised an
+                // "Undefined property: stdClass::$plan_id" warning on PHP 8.
+                $this->plan_id = isset( $site->plan_id ) ? $site->plan_id : null;
             }
 
             if ( ! is_bool( $this->is_disconnected ) ) {