diff --git a/docs/v2/accounting/index.html b/docs/v2/accounting/index.html
index 404d04ee..6af4b93b 100644
--- a/docs/v2/accounting/index.html
+++ b/docs/v2/accounting/index.html
@@ -4193,7 +4193,7 @@
     "Class" : {
       "type" : "string",
       "description" : "Organisation Classes describe which plan the Xero organisation is on (e.g. DEMO, TRIAL, PREMIUM)",
-      "enum" : [ "DEMO", "TRIAL", "STARTER", "STANDARD", "PREMIUM", "PREMIUM_20", "PREMIUM_50", "PREMIUM_100", "LEDGER", "GST_CASHBOOK", "NON_GST_CASHBOOK", "ULTIMATE", "LITE", "ULTIMATE_10", "ULTIMATE_20", "ULTIMATE_50", "ULTIMATE_100", "IGNITE", "GROW", "COMPREHENSIVE" ]
+      "enum" : [ "DEMO", "TRIAL", "STARTER", "STANDARD", "PREMIUM", "PREMIUM_20", "PREMIUM_50", "PREMIUM_100", "LEDGER", "GST_CASHBOOK", "NON_GST_CASHBOOK", "ULTIMATE", "LITE", "ULTIMATE_10", "ULTIMATE_20", "ULTIMATE_50", "ULTIMATE_100", "IGNITE", "GROW", "COMPREHENSIVE", "SIMPLE" ]
     },
     "Edition" : {
       "type" : "string",
@@ -6338,7 +6338,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="Accounting"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="Accounting"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="Accounting"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="Accounting"><a href="#api-Accounting">Methods</a></li>
               <li data-group="Accounting" data-name="createAccount" class="">
                 <a href="#api-Accounting-createAccount">createAccount</a>
diff --git a/docs/v2/appstore/index.html b/docs/v2/appstore/index.html
index 81520152..e954597f 100644
--- a/docs/v2/appstore/index.html
+++ b/docs/v2/appstore/index.html
@@ -1240,7 +1240,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="AppStore"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="AppStore"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="AppStore"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="AppStore"><a href="#api-AppStore">Methods</a></li>
               <li data-group="AppStore" data-name="getSubscription" class="">
                 <a href="#api-AppStore-getSubscription">getSubscription</a>
diff --git a/docs/v2/assets/index.html b/docs/v2/assets/index.html
index f87a4bab..2d763d0e 100644
--- a/docs/v2/assets/index.html
+++ b/docs/v2/assets/index.html
@@ -1391,7 +1391,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="Asset"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="Asset"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="Asset"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="Asset"><a href="#api-Asset">Methods</a></li>
               <li data-group="Asset" data-name="createAsset" class="">
                 <a href="#api-Asset-createAsset">createAsset</a>
diff --git a/docs/v2/files/index.html b/docs/v2/files/index.html
index 7a6bcedf..a9b9269a 100644
--- a/docs/v2/files/index.html
+++ b/docs/v2/files/index.html
@@ -1169,7 +1169,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="Files"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="Files"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="Files"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="Files"><a href="#api-Files">Methods</a></li>
               <li data-group="Files" data-name="createFileAssociation" class="">
                 <a href="#api-Files-createFileAssociation">createFileAssociation</a>
diff --git a/docs/v2/finance/index.html b/docs/v2/finance/index.html
index d9a163f6..61e6e1d0 100644
--- a/docs/v2/finance/index.html
+++ b/docs/v2/finance/index.html
@@ -2715,7 +2715,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="Finance"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="Finance"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="Finance"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="Finance"><a href="#api-Finance">Methods</a></li>
               <li data-group="Finance" data-name="getAccountingActivityAccountUsage" class="">
                 <a href="#api-Finance-getAccountingActivityAccountUsage">getAccountingActivityAccountUsage</a>
diff --git a/docs/v2/payroll_au/index.html b/docs/v2/payroll_au/index.html
index 4584ffb4..e5275941 100644
--- a/docs/v2/payroll_au/index.html
+++ b/docs/v2/payroll_au/index.html
@@ -3411,7 +3411,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="PayrollAu"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="PayrollAu"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="PayrollAu"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="PayrollAu"><a href="#api-PayrollAu">Methods</a></li>
               <li data-group="PayrollAu" data-name="approveLeaveApplication" class="">
                 <a href="#api-PayrollAu-approveLeaveApplication">approveLeaveApplication</a>
diff --git a/docs/v2/payroll_nz/index.html b/docs/v2/payroll_nz/index.html
index ffba3c6c..ff2e5bab 100644
--- a/docs/v2/payroll_nz/index.html
+++ b/docs/v2/payroll_nz/index.html
@@ -4086,7 +4086,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="PayrollNz"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="PayrollNz"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="PayrollNz"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="PayrollNz"><a href="#api-PayrollNz">Methods</a></li>
               <li data-group="PayrollNz" data-name="approveTimesheet" class="">
                 <a href="#api-PayrollNz-approveTimesheet">approveTimesheet</a>
diff --git a/docs/v2/payroll_uk/index.html b/docs/v2/payroll_uk/index.html
index 18a42ccd..5d4bbd4e 100644
--- a/docs/v2/payroll_uk/index.html
+++ b/docs/v2/payroll_uk/index.html
@@ -2562,7 +2562,7 @@
   "type" : "string",
   "description" : "The employee's NI Category letter.",
   "example" : "I",
-  "enum" : [ "A", "B", "C", "D", "E", "F", "H", "I", "J", "K", "L", "M", "N", "S", "V", "X", "Z" ]
+  "enum" : [ "A", "B", "C", "F", "H", "I", "J", "L", "M", "S", "V", "X", "Z", "D", "E", "K", "N" ]
 };
       defs["NICategory_oneOf"] = {
   "title" : "",
@@ -3599,7 +3599,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="PayrollUk"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="PayrollUk"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="PayrollUk"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="PayrollUk"><a href="#api-PayrollUk">Methods</a></li>
               <li data-group="PayrollUk" data-name="approveTimesheet" class="">
                 <a href="#api-PayrollUk-approveTimesheet">approveTimesheet</a>
diff --git a/docs/v2/projects/index.html b/docs/v2/projects/index.html
index 03f1fc46..9d796e39 100644
--- a/docs/v2/projects/index.html
+++ b/docs/v2/projects/index.html
@@ -1461,7 +1461,7 @@
           <nav id="scrollingNav">
             <ul class="sidenav nav nav-list">
               <li class="nav-header" data-group="Project"><strong>SDK: </strong><span id='sdk-name'></span></li>
-              <li class="nav-header" data-group="Project"><strong>VSN: </strong>9.0.0</li>
+              <li class="nav-header" data-group="Project"><strong>VSN: </strong>9.1.0</li>
               <li class="nav-header" data-group="Project"><a href="#api-Project">Methods</a></li>
               <li data-group="Project" data-name="createProject" class="">
                 <a href="#api-Project-createProject">createProject</a>
diff --git a/lib/Api/AccountingApi.php b/lib/Api/AccountingApi.php
index d338bb13..77b896a9 100644
--- a/lib/Api/AccountingApi.php
+++ b/lib/Api/AccountingApi.php
@@ -14,7 +14,7 @@
  *
  * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/AppStoreApi.php b/lib/Api/AppStoreApi.php
index 93a74ace..4d756598 100644
--- a/lib/Api/AppStoreApi.php
+++ b/lib/Api/AppStoreApi.php
@@ -14,7 +14,7 @@
  *
  * These endpoints are for Xero Partners to interact with the App Store Billing platform
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/AssetApi.php b/lib/Api/AssetApi.php
index aca4bba2..1b7f2cab 100644
--- a/lib/Api/AssetApi.php
+++ b/lib/Api/AssetApi.php
@@ -14,7 +14,7 @@
  *
  * The Assets API exposes fixed asset related functions of the Xero Accounting application and can be used for a variety of purposes such as creating assets, retrieving asset valuations etc.
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/FilesApi.php b/lib/Api/FilesApi.php
index 909c65b8..35ba7d34 100644
--- a/lib/Api/FilesApi.php
+++ b/lib/Api/FilesApi.php
@@ -14,7 +14,7 @@
  *
  * These endpoints are specific to Xero Files API
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/FinanceApi.php b/lib/Api/FinanceApi.php
index efa16fda..03694ffd 100644
--- a/lib/Api/FinanceApi.php
+++ b/lib/Api/FinanceApi.php
@@ -14,7 +14,7 @@
  *
  * The Finance API is a collection of endpoints which customers can use in the course of a loan application, which may assist lenders to gain the confidence they need to provide capital.
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/IdentityApi.php b/lib/Api/IdentityApi.php
index 42b6ac88..43277b20 100644
--- a/lib/Api/IdentityApi.php
+++ b/lib/Api/IdentityApi.php
@@ -14,7 +14,7 @@
  *
  * These endpoints are related to managing authentication tokens and identity for Xero API
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/PayrollAuApi.php b/lib/Api/PayrollAuApi.php
index a152d972..33bf3ac6 100644
--- a/lib/Api/PayrollAuApi.php
+++ b/lib/Api/PayrollAuApi.php
@@ -14,7 +14,7 @@
  *
  * This is the Xero Payroll API for orgs in Australia region.
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/PayrollNzApi.php b/lib/Api/PayrollNzApi.php
index 0660bc38..2f4744dc 100644
--- a/lib/Api/PayrollNzApi.php
+++ b/lib/Api/PayrollNzApi.php
@@ -14,7 +14,7 @@
  *
  * This is the Xero Payroll API for orgs in the NZ region.
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/PayrollUkApi.php b/lib/Api/PayrollUkApi.php
index 04233f04..646ecfa8 100644
--- a/lib/Api/PayrollUkApi.php
+++ b/lib/Api/PayrollUkApi.php
@@ -14,7 +14,7 @@
  *
  * This is the Xero Payroll API for orgs in the UK region.
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Api/ProjectApi.php b/lib/Api/ProjectApi.php
index a3d497cc..093ecdb0 100644
--- a/lib/Api/ProjectApi.php
+++ b/lib/Api/ProjectApi.php
@@ -14,7 +14,7 @@
  *
  * This is the Xero Projects API
  *
- * OpenAPI spec version: 8.0.0
+ * OpenAPI spec version: 8.1.0
  * Contact: api@xero.com
  * Generated by: https://openapi-generator.tech
  * OpenAPI Generator version: 5.4.0
diff --git a/lib/Configuration.php b/lib/Configuration.php
index 99b61efb..aaa563d5 100644
--- a/lib/Configuration.php
+++ b/lib/Configuration.php
@@ -696,8 +696,8 @@ public static function toDebugReport()
         $report  = 'PHP SDK (XeroAPI\XeroPHP) Debug Report:' . PHP_EOL;
         $report .= '    OS: ' . php_uname() . PHP_EOL;
         $report .= '    PHP Version: ' . PHP_VERSION . PHP_EOL;
-        $report .= '    OpenAPI Spec Version: 8.0.0' . PHP_EOL;
-        $report .= '    SDK Package Version: 9.0.0' . PHP_EOL;
+        $report .= '    OpenAPI Spec Version: 8.1.0' . PHP_EOL;
+        $report .= '    SDK Package Version: 9.1.0' . PHP_EOL;
         $report .= '    Temp Folder Path: ' . self::getDefaultConfiguration()->getTempFolderPath() . PHP_EOL;
 
         return $report;
diff --git a/lib/Models/Accounting/Organisation.php b/lib/Models/Accounting/Organisation.php
index 6f822073..7b4ebfa5 100644
--- a/lib/Models/Accounting/Organisation.php
+++ b/lib/Models/Accounting/Organisation.php
@@ -398,6 +398,7 @@ public function getModelName()
     const MODEL_CLASS_IGNITE = 'IGNITE';
     const MODEL_CLASS_GROW = 'GROW';
     const MODEL_CLASS_COMPREHENSIVE = 'COMPREHENSIVE';
+    const MODEL_CLASS_SIMPLE = 'SIMPLE';
     const EDITION_BUSINESS = 'BUSINESS';
     const EDITION_PARTNER = 'PARTNER';
     
@@ -545,6 +546,7 @@ public function getClassAllowableValues()
             self::MODEL_CLASS_IGNITE,
             self::MODEL_CLASS_GROW,
             self::MODEL_CLASS_COMPREHENSIVE,
+            self::MODEL_CLASS_SIMPLE,
         ];
     }