I presented the link above, but I quote it just in case.
As we as we are focused moving all Memrise learners over to our Learn, Immerse, Communicate experience, it is no longer possible to revert to the old experience in the Android and iOS apps.
If you wish to go back to the old Memrise experience, you will need to follow the steps below on the website.
⚠️ Please note you will not be able to enrol in any official content in the Classic experience as this now lives in the new experience. You should only return to the Classic experience to learn community-created courses.
How to opt out on web
1. Go directly to one of your community course links or go to https://www.memrise.com/en/community-courses and click on any community course.
2. Start a learning session (you can click out part-way through).
3. This will return you to https://app.memrise.com/dashboard.