diff --git a/docs/payroll-uk/index.html b/docs/payroll-uk/index.html
index 5c96b83b..38c2fbd3 100644
--- a/docs/payroll-uk/index.html
+++ b/docs/payroll-uk/index.html
@@ -1595,6 +1595,16 @@
       "format" : "date-time",
       "x-is-datetime" : true
     },
+    "niCategory" : {
+      "$ref" : "#/components/schemas/NICategoryLetter"
+    },
+    "niCategories" : {
+      "type" : "array",
+      "description" : "The employee's NI categories",
+      "items" : {
+        "$ref" : "#/components/schemas/NICategory"
+      }
+    },
     "nationalInsuranceNumber" : {
       "type" : "string",
       "description" : "National insurance number of the employee",
@@ -2262,7 +2272,7 @@
 };
       defs["Employment"] = {
   "title" : "",
-  "required" : [ "EmployeeNumber", "NICategory", "PayrollCalendarID", "StartDate" ],
+  "required" : [ "EmployeeNumber", "NICategories", "PayrollCalendarID", "StartDate" ],
   "type" : "object",
   "properties" : {
     "payrollCalendarID" : {
@@ -2282,10 +2292,14 @@
       "example" : "7"
     },
     "niCategory" : {
-      "type" : "string",
-      "description" : "The NI Category of the employee",
-      "example" : "A",
-      "enum" : [ "A", "B", "C", "F", "H", "I", "J", "L", "M", "S", "V", "X", "Z" ]
+      "$ref" : "#/components/schemas/NICategoryLetter"
+    },
+    "niCategories" : {
+      "type" : "array",
+      "description" : "The employee's NI categories",
+      "items" : {
+        "$ref" : "#/components/schemas/NICategory"
+      }
     }
   },
   "description" : ""
@@ -2502,6 +2516,75 @@
     }
   },
   "description" : ""
+};
+      defs["NICategory"] = {
+  "title" : "",
+  "required" : [ "niCategory", "workplacePostcode" ],
+  "type" : "object",
+  "properties" : {
+    "startDate" : {
+      "type" : "string",
+      "description" : "The start date of the NI category (YYYY-MM-DD)",
+      "format" : "date",
+      "example" : "2024-12-02",
+      "x-is-date" : true
+    },
+    "niCategory" : {
+      "$ref" : "#/components/schemas/NICategoryLetter"
+    },
+    "niCategoryID" : {
+      "type" : "number",
+      "description" : "Xero unique identifier for the NI category",
+      "example" : 15
+    },
+    "dateFirstEmployedAsCivilian" : {
+      "type" : "string",
+      "description" : "The date in which the employee was first employed as a civilian (YYYY-MM-DD)",
+      "format" : "date",
+      "example" : "2024-12-02",
+      "x-is-date" : true
+    },
+    "workplacePostcode" : {
+      "type" : "string",
+      "description" : "The workplace postcode",
+      "example" : "SW1A 1AA"
+    }
+  },
+  "description" : "",
+  "oneOf" : [ {
+    "$ref" : "#/components/schemas/NICategory_oneOf"
+  }, {
+    "$ref" : "#/components/schemas/NICategory_oneOf_1"
+  } ]
+};
+      defs["NICategoryLetter"] = {
+  "title" : "",
+  "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" ]
+};
+      defs["NICategory_oneOf"] = {
+  "title" : "",
+  "required" : [ "workplacePostcode" ],
+  "properties" : {
+    "niCategory" : {
+      "type" : "string",
+      "enum" : [ "F", "I", "L", "S", "N", "E", "D", "K" ]
+    }
+  },
+  "description" : ""
+};
+      defs["NICategory_oneOf_1"] = {
+  "title" : "",
+  "required" : [ "dateFirstEmployedAsCivilian" ],
+  "properties" : {
+    "niCategory" : {
+      "type" : "string",
+      "enum" : [ "V" ]
+    }
+  },
+  "description" : ""
 };
       defs["Pagination"] = {
   "title" : "",
@@ -5715,6 +5798,8 @@ <h3>Usage and SDK Samples</h3>
   startDate: startDate
 }; 
 
+const niCategories: NICategories = { 
+
 try {
   const response = await xero.accountingApi.createEmployment(xeroTenantId, employeeID, employment, idempotencyKey);
   console.log(response.body || response.response.statusCode)
@@ -5846,7 +5931,7 @@ <h2>Parameters</h2>
       "schema" : {
         "$ref" : "#/components/schemas/Employment"
       },
-      "example" : "{ \"PayrollCalendarID\": \"216d80e6-af55-47b1-b718-9457c3f5d2fe\", \"StartDate\": \"2020-04-01\", \"EmployeeNumber\": \"123ABC\", \"NICategory\": \"A\" }"
+      "example" : "{ \"PayrollCalendarID\": \"216d80e6-af55-47b1-b718-9457c3f5d2fe\", \"StartDate\": \"2020-04-01\", \"NICategories\": [ { \"NICategory\": \"A\", \"StartDate\": \"2020-05-01\" } ], \"EmployeeNumber\": \"123ABC\" }"
     }
   },
   "required" : true
diff --git a/src/gen/model/payroll-uk/employee.ts b/src/gen/model/payroll-uk/employee.ts
index c405e6fe..05551438 100644
--- a/src/gen/model/payroll-uk/employee.ts
+++ b/src/gen/model/payroll-uk/employee.ts
@@ -1,4 +1,6 @@
 import { Address } from '././address';
+import { NICategory } from '././nICategory';
+import { NICategoryLetter } from '././nICategoryLetter';
 
 export class Employee {
     /**
@@ -54,6 +56,11 @@ export class Employee {
     * UTC timestamp when the employee was created in Xero
     */
     'createdDateUTC'?: Date;
+    'niCategory'?: NICategoryLetter;
+    /**
+    * The employee\'s NI categories
+    */
+    'niCategories'?: Array<NICategory>;
     /**
     * National insurance number of the employee
     */
@@ -136,6 +143,16 @@ export class Employee {
             "baseName": "createdDateUTC",
             "type": "Date"
         },
+        {
+            "name": "niCategory",
+            "baseName": "niCategory",
+            "type": "NICategoryLetter"
+        },
+        {
+            "name": "niCategories",
+            "baseName": "niCategories",
+            "type": "Array<NICategory>"
+        },
         {
             "name": "nationalInsuranceNumber",
             "baseName": "nationalInsuranceNumber",
diff --git a/src/gen/model/payroll-uk/employment.ts b/src/gen/model/payroll-uk/employment.ts
index af76f3c4..db85b7fc 100644
--- a/src/gen/model/payroll-uk/employment.ts
+++ b/src/gen/model/payroll-uk/employment.ts
@@ -1,3 +1,5 @@
+import { NICategory } from '././nICategory';
+import { NICategoryLetter } from '././nICategoryLetter';
 
 export class Employment {
     /**
@@ -12,10 +14,11 @@ export class Employment {
     * The employment number of the employee
     */
     'employeeNumber'?: string;
+    'niCategory'?: NICategoryLetter;
     /**
-    * The NI Category of the employee
+    * The employee\'s NI categories
     */
-    'niCategory'?: Employment.NiCategoryEnum;
+    'niCategories'?: Array<NICategory>;
 
     static discriminator: string | undefined = undefined;
 
@@ -38,7 +41,12 @@ export class Employment {
         {
             "name": "niCategory",
             "baseName": "niCategory",
-            "type": "Employment.NiCategoryEnum"
+            "type": "NICategoryLetter"
+        },
+        {
+            "name": "niCategories",
+            "baseName": "niCategories",
+            "type": "Array<NICategory>"
         }    ];
 
     static getAttributeTypeMap() {
@@ -46,20 +54,3 @@ export class Employment {
     }
 }
 
-export namespace Employment {
-    export enum NiCategoryEnum {
-        A = <any> 'A',
-        B = <any> 'B',
-        C = <any> 'C',
-        F = <any> 'F',
-        H = <any> 'H',
-        I = <any> 'I',
-        J = <any> 'J',
-        L = <any> 'L',
-        M = <any> 'M',
-        S = <any> 'S',
-        V = <any> 'V',
-        X = <any> 'X',
-        Z = <any> 'Z'
-    }
-}
diff --git a/src/gen/model/payroll-uk/models.ts b/src/gen/model/payroll-uk/models.ts
index 9b62edfc..73ad438f 100644
--- a/src/gen/model/payroll-uk/models.ts
+++ b/src/gen/model/payroll-uk/models.ts
@@ -55,6 +55,10 @@ export * from '././leavePeriods';
 export * from '././leaveType';
 export * from '././leaveTypeObject';
 export * from '././leaveTypes';
+export * from '././nICategory';
+export * from '././nICategoryLetter';
+export * from '././nICategoryOneOf';
+export * from '././nICategoryOneOf1';
 export * from '././pagination';
 export * from '././payRun';
 export * from '././payRunCalendar';
@@ -146,6 +150,10 @@ import { LeavePeriods } from '././leavePeriods';
 import { LeaveType } from '././leaveType';
 import { LeaveTypeObject } from '././leaveTypeObject';
 import { LeaveTypes } from '././leaveTypes';
+import { NICategory } from '././nICategory';
+import { NICategoryLetter } from '././nICategoryLetter';
+import { NICategoryOneOf } from '././nICategoryOneOf';
+import { NICategoryOneOf1 } from '././nICategoryOneOf1';
 import { Pagination } from '././pagination';
 import { PayRun } from '././payRun';
 import { PayRunCalendar } from '././payRunCalendar';
@@ -207,8 +215,10 @@ let enumsMap: {[index: string]: any} = {
         "EmployeeStatutoryLeaveSummary.TypeEnum": EmployeeStatutoryLeaveSummary.TypeEnum,
         "EmployeeStatutoryLeaveSummary.StatusEnum": EmployeeStatutoryLeaveSummary.StatusEnum,
         "EmployeeStatutorySickLeave.EntitlementFailureReasonsEnum": EmployeeStatutorySickLeave.EntitlementFailureReasonsEnum,
-        "Employment.NiCategoryEnum": Employment.NiCategoryEnum,
         "LeavePeriod.PeriodStatusEnum": LeavePeriod.PeriodStatusEnum,
+        "NICategoryLetter": NICategoryLetter,
+        "NICategoryOneOf.NiCategoryEnum": NICategoryOneOf.NiCategoryEnum,
+        "NICategoryOneOf1.NiCategoryEnum": NICategoryOneOf1.NiCategoryEnum,
         "PayRun.PayRunStatusEnum": PayRun.PayRunStatusEnum,
         "PayRun.PayRunTypeEnum": PayRun.PayRunTypeEnum,
         "PayRun.CalendarTypeEnum": PayRun.CalendarTypeEnum,
@@ -279,6 +289,9 @@ let typeMap: {[index: string]: any} = {
     "LeaveType": LeaveType,
     "LeaveTypeObject": LeaveTypeObject,
     "LeaveTypes": LeaveTypes,
+    "NICategory": NICategory,
+    "NICategoryOneOf": NICategoryOneOf,
+    "NICategoryOneOf1": NICategoryOneOf1,
     "Pagination": Pagination,
     "PayRun": PayRun,
     "PayRunCalendar": PayRunCalendar,
diff --git a/src/gen/model/payroll-uk/nICategory.ts b/src/gen/model/payroll-uk/nICategory.ts
new file mode 100644
index 00000000..f0bd13df
--- /dev/null
+++ b/src/gen/model/payroll-uk/nICategory.ts
@@ -0,0 +1,59 @@
+import { NICategoryLetter } from '././nICategoryLetter';
+import { NICategoryOneOf } from '././nICategoryOneOf';
+import { NICategoryOneOf1 } from '././nICategoryOneOf1';
+
+export class NICategory {
+    /**
+    * The start date of the NI category (YYYY-MM-DD)
+    */
+    'startDate'?: string;
+    'niCategory': NICategoryLetter;
+    /**
+    * Xero unique identifier for the NI category
+    */
+    'niCategoryID'?: number;
+    /**
+    * The date in which the employee was first employed as a civilian (YYYY-MM-DD)
+    */
+    'dateFirstEmployedAsCivilian'?: string;
+    /**
+    * The workplace postcode
+    */
+    'workplacePostcode': string;
+
+    static discriminator: string | undefined = undefined;
+
+    static attributeTypeMap: Array<{name: string, baseName: string, type: string}> = [
+        {
+            "name": "startDate",
+            "baseName": "startDate",
+            "type": "string"
+        },
+        {
+            "name": "niCategory",
+            "baseName": "niCategory",
+            "type": "NICategoryLetter"
+        },
+        {
+            "name": "niCategoryID",
+            "baseName": "niCategoryID",
+            "type": "number"
+        },
+        {
+            "name": "dateFirstEmployedAsCivilian",
+            "baseName": "dateFirstEmployedAsCivilian",
+            "type": "string"
+        },
+        {
+            "name": "workplacePostcode",
+            "baseName": "workplacePostcode",
+            "type": "string"
+        }    ];
+
+    static getAttributeTypeMap() {
+        return NICategory.attributeTypeMap;
+    }
+}
+
+export namespace NICategory {
+}
diff --git a/src/gen/model/payroll-uk/nICategoryLetter.ts b/src/gen/model/payroll-uk/nICategoryLetter.ts
new file mode 100644
index 00000000..b989a77d
--- /dev/null
+++ b/src/gen/model/payroll-uk/nICategoryLetter.ts
@@ -0,0 +1,23 @@
+
+/**
+* The employee\'s NI Category letter.
+*/
+export enum NICategoryLetter {
+    A = <any> 'A',
+    B = <any> 'B',
+    C = <any> 'C',
+    D = <any> 'D',
+    E = <any> 'E',
+    F = <any> 'F',
+    H = <any> 'H',
+    I = <any> 'I',
+    J = <any> 'J',
+    K = <any> 'K',
+    L = <any> 'L',
+    M = <any> 'M',
+    N = <any> 'N',
+    S = <any> 'S',
+    V = <any> 'V',
+    X = <any> 'X',
+    Z = <any> 'Z'
+}
diff --git a/src/gen/model/payroll-uk/nICategoryOneOf.ts b/src/gen/model/payroll-uk/nICategoryOneOf.ts
new file mode 100644
index 00000000..f30ed486
--- /dev/null
+++ b/src/gen/model/payroll-uk/nICategoryOneOf.ts
@@ -0,0 +1,30 @@
+
+export class NICategoryOneOf {
+    'niCategory'?: NICategoryOneOf.NiCategoryEnum;
+
+    static discriminator: string | undefined = undefined;
+
+    static attributeTypeMap: Array<{name: string, baseName: string, type: string}> = [
+        {
+            "name": "niCategory",
+            "baseName": "niCategory",
+            "type": "NICategoryOneOf.NiCategoryEnum"
+        }    ];
+
+    static getAttributeTypeMap() {
+        return NICategoryOneOf.attributeTypeMap;
+    }
+}
+
+export namespace NICategoryOneOf {
+    export enum NiCategoryEnum {
+        F = <any> 'F',
+        I = <any> 'I',
+        L = <any> 'L',
+        S = <any> 'S',
+        N = <any> 'N',
+        E = <any> 'E',
+        D = <any> 'D',
+        K = <any> 'K'
+    }
+}
diff --git a/src/gen/model/payroll-uk/nICategoryOneOf1.ts b/src/gen/model/payroll-uk/nICategoryOneOf1.ts
new file mode 100644
index 00000000..e0b45f38
--- /dev/null
+++ b/src/gen/model/payroll-uk/nICategoryOneOf1.ts
@@ -0,0 +1,23 @@
+
+export class NICategoryOneOf1 {
+    'niCategory'?: NICategoryOneOf1.NiCategoryEnum;
+
+    static discriminator: string | undefined = undefined;
+
+    static attributeTypeMap: Array<{name: string, baseName: string, type: string}> = [
+        {
+            "name": "niCategory",
+            "baseName": "niCategory",
+            "type": "NICategoryOneOf1.NiCategoryEnum"
+        }    ];
+
+    static getAttributeTypeMap() {
+        return NICategoryOneOf1.attributeTypeMap;
+    }
+}
+
+export namespace NICategoryOneOf1 {
+    export enum NiCategoryEnum {
+        V = <any> 'V'
+    }
+}