As you may already know, a new SharePoint Online administration portal has been underway for quite some time now.
This new administration portal is now becoming the default SharePoint Online administration experience over the next few months, with tenant with 50 users or less being targeted first (expected roll out start schedule for March 2019).
That being said, you can:
- block the new administration portal being the default experience
- or come back to the now ‘legacy’ SharePoint Online administration portal
Turn off the new experience
To block the new portal being the default experience you need to first go to the new portal to turn Off the new setting “Default Admin Experience”
Access your ‘current’ SharePoint Online administration portal (https://<your tenant>-admin.sharepoint.com/) and click on the Try it now button available in the banner notifying the new portal
From there access the Settings option from the left menu and open the “Default admin experience”option to turn the toggle to Off
Going back to the old portal
If you choose to keep on going with the new administration portal, you can at any time go back to the ‘old/legacy’ administration portal by using the Classic SharePoint admin experience option available on the left menu