Until August 31st, 2020 Pages from the old application will be available. You can still edit those Pages, but can no longer include them in new Campaigns that you are sending out.
Unfortunately those old Pages cannot be transferred to Pages 2.
You can visit the previous Pages application using the banner on the Pages dashboard.
The previous Pages app will be available in edit-only mode. This means that you can still see and edit all your existing Pages.
You can keep using the old Pages app until August 31st, 2020. After that date Pages 2 will completely replace the old Pages app and you will no longer be able to access the Pages you had in the old app.