How to migrate from Hosted Redash ver7 to GCE?

I prepared GCE redash ver8, and using redash-migrate to migrate data.
50% of redash-migrate users failed,
then redash-migrate queries failed with “no user”.

All redash-migrate support is over V9. So I need to update both to V10.
I can make V10 GCE instance, but how can I update hosted redash from V7 to V10?

Also, docs say another choise is to dump PostgreSQL and import it to new one.
How can I log in to hosted redash?

What do you mean by hosted Redash?