The headline date for Azure CDN Standard from Microsoft (classic) retirement is 30 September 2027. Most teams read that and filed it as a 2027 problem.
The billing changed in April 2026.
What triggered it
Azure CDN classic used CNAME-based Domain Control Validation for managed certificates. Microsoft deprecated CNAME DCV in August 2025. Certificates on classic SKUs were renewed one final time and set to expire 14 April 2026, with no further renewal possible on the classic SKU.
To prevent HTTPS disruption, Microsoft began automatically migrating classic profiles to Azure Front Door Standard or Premium from 10 April 2026. Customers had until 9 April to set a feature flag to opt out. Miss that window and the migration happened automatically.
What changed on the bill
CDN classic is primarily a bandwidth-billed product. Low-traffic and dormant profiles cost very little, often effectively £0/month.
Azure Front Door Standard uses a different model. There's a base cost per profile regardless of traffic. Profiles that cost near nothing on CDN classic can run around £30/month on AFD Standard. Per profile. Before any traffic.
Organisations with multiple classic CDN profiles across different subscriptions (test environments, legacy projects, old proofs of concept) may have several of these now accruing charges they weren't expecting.
What to do now
Audit your profiles. In the Azure portal, go to Front Doors and filter Pricing tier = Classic, Service type = Microsoft CDN. If you've been migrated, those will now show as Standard or Premium.
Check Cost Management. Filter from 10 April onwards for Azure Front Door charges. Any profile with standing charges and no meaningful traffic is either dormant or misconfigured.
Delete what's not needed. Deleting an unused profile stops the charges immediately. If the migration was automatic on resources that weren't in use, a support ticket requesting a credit is worth raising.
The 2027 deadline still applies
For classic CDN profiles still in active use, the retirement deadline remains 30 September 2027. New classic resources can't be created as of August 2025, so any remaining classic profiles predate that cutoff.
The managed certificate issue brought the billing change forward for a significant number of profiles. For everything else, migration is still a 2027 task. But any new CDN requirements should use Azure Front Door Standard from the start.
Looking for a structured view of dormant resources and unexpected charges across your Azure estate? Our free cost assessment covers this as part of the standard review.