I’m upgrading Fullcalendar from 5 to 6, I use Vue 2.6.12 with Webpack & Typescript.
The application runs fine on dev but it’s not building:

vue-cli-service build

ERROR in /usr/srv/client/node_modules/@fullcalendar/vue/dist/FullCalendar.d.ts(4,29):
4:29 Generic type 'ExtendedVue' requires 5 type argument(s).
    2 | import { Calendar, CalendarOptions } from '@fullcalendar/core';
    3 | import { CustomRendering } from '@fullcalendar/core/internal';
  > 4 | declare const FullCalendar: import("vue/types/vue.js").ExtendedVue<Vue<Record<string, any>, Record<string, any>, never, never, (event: string, ...args: any[]) => Vue<Record<string, any>, Record<string, any>, never, never, any>>, {
      |                             ^
    5 |     renderId: number;
    6 |     customRenderingMap: Map<string, CustomRendering<any>>;
    7 | }, {

Complaining about ExtendedVue expects 5 type arguments and I indeed count 8 here

Original type file:

import Vue from 'vue';
import { Calendar, CalendarOptions } from '@fullcalendar/core';
import { CustomRendering } from '@fullcalendar/core/internal';
declare const FullCalendar: import("vue/types/vue.js").ExtendedVue<Vue<Record<string, any>, Record<string, any>, never, never, (event: string, ...args: any[]) => Vue<Record<string, any>, Record<string, any>, never, never, any>>, {
    renderId: number;
    customRenderingMap: Map<string, CustomRendering<any>>;
}, {
    getApi(): Calendar;
    buildOptions(suppliedOptions: CalendarOptions | undefined): CalendarOptions;
}, unknown, {
    options: CalendarOptions;
}, {}, import("vue/types/v3-component-options.js").ComponentOptionsMixin, import("vue/types/v3-component-options.js").ComponentOptionsMixin>;
export default FullCalendar;

package.json extract:

{
  "dependencies": {
    "@fullcalendar/core": "^6.1.15",
    "@fullcalendar/daygrid": "^6.1.15",
    "@fullcalendar/interaction": "^6.1.15",
    "@fullcalendar/timegrid": "^6.1.15",
    "@fullcalendar/vue": "^6.1.15",
    "vue": "^2.6.10",
//...
  },
}

What can I do about that ?
Please don’t tell me I need to go Vue 3, It’d be too much of a PITA for my project and it’s not supposed to be an issue (5 to 6 migration guide)