MDBVue has broken custom colors with the latest version of S

Hi, I have just upgraded to mdbVue 6.7.1. I have added the following colors to custom-variables.css (which I have always used).

// Your custom variables $primary-color: #923f82; $secondary-color: #9dbe44;

I have also upgraded SASS.

I now get the error:

Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
SassError: $color: #9dbe44 is not a color. ╷ 819 │ $switch-color-checked-lever-bg: desaturate(lighten($secondary-color, 25%), 25%) !default; │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ╵ node_modules\mdbvue\lib\scss\core_colors.scss 819:46 @import node_modules\mdbvue\lib\scss\mdb-free.scss 12:9 @import node_modules\mdbvue\lib\scss\mdb-pro.scss 2:9 @import src\app.vue 292:9 root stylesheet

@ ./node_modules/vue-style-loader??ref--8-oneOf-1-0!./node_modules/css-loader/dist/cjs.js??ref--8-oneOf-1-1!./node_modules/vue-loader/lib/loaders/stylePostLoader.js!./node_modules/postcss-loader/src??ref--8-oneOf-1-2!./node_modules/sass-loader/dist/cjs.js??ref--8-oneOf-1-3!./node_modules/cache-loader/dist/cjs.js??ref--0-0!./node_modules/vue-loader/lib??vue-loader-options!./src/app.vue?vue&type=style&index=0&lang=scss& 4:14-416 14:3-18:5 15:22-424 @ ./src/app.vue?vue&type=style&index=0&lang=scss& @ ./src/app.vue @ ./src/main.js @ multi (webpack)-dev-server/client?http://192.168.178.56:8080&sockPath=/sockjs-node (webpack)/hot/dev-server.js ./src/main.js

It appears that mdbVue is incompatible with the latest version of SASS. How do I fix this please?

Paul.