There are some major changes between the old and new systems. The most salient ones are documented here.
Are there any features being removed?
- Notifications within the Portal are being removed. Going forward, only email notification are available.
- Subscriptions can no longer be paused. For subscriptions producing too many notifications, consider changing the update frequency (or deleting them) instead.
- "Fast" notifications are now "hourly"; other cadences remain the same.
What new features are there?
- Duplicate subscriptions are automatically rejected, to prevent getting multiple emails for the same changes.
- You can now subscribe directly to a dataset, using a dataset ID.
- A better email template makes it easier to understand which files have changed. This includes a JSON file that indicates exactly which files have changed; the JSON file can be passed directly to astroquery.mast to download the files you've subscribed to.
What happens to subscriptions previously made in the Portal?
All users with subscriptions to MAST data received a pre-migration advisory email on 2026 May 4, followed up by a post switchover update on the 26th. In most cases, your subscriptions have been migrated seamlessly. If you created an invalid subscription (e.g., to JWST program -42), this was not migrated. Additionally, any "fast" subscriptions have been converted into the fastest option available: hourly.
Subscription notifications within the Portal are no longer available; this is now handled entirely through email.
Why can't I make subscriptions in the Portal anymore?
The Portal is built on an old tech stack that we do not have the capacity to maintain. The new subscriptions service helps reduce MAST's technical debt while offering a service that is faster for users.