Twilio published the retirement calendar for Functions (Classic). Two dates, both stated in the official notice.
The two dates
September 13, 2026 — from this date on, no new Functions (Classic) or assets can be created. Everything that already exists keeps running, and you can still edit and deploy existing code during the window.
Between September 14 and October 26, 2026 — Twilio automatically migrates every active Function (Classic) to the new Functions: existing URLs, function and asset names, environment variables, and the published code.
What this means if you have automation in production
If a support flow, a call-routing rule or a webhook in your business was built on Functions (Classic), it does not stop on September 13. That date only closes the door on creating new ones. The real change happens inside the migration window.
The honest caveat
Automatic migration handles most of the work, and that deserves to be said plainly. What automatic migration tends to leave behind is custom dependencies and legacy configuration. So the test belongs before October 26, not after — once the window closes, the old environment is no longer there to compare against.
What to do now
- Inventory which Functions (Classic) exist in your account today.
- Run each one in the new environment and diff the output.
- Write down every external dependency and environment variable the flow touches.
Next dates
September 13, 2026 — creation of new Functions (Classic) ends.
October 26, 2026 — the automatic migration window closes.
Source
Twilio — Functions (Classic) deprecation, twilio.com/en-us/changelog.
One honest note: there is no universal multiplier. The outcome depends on your industry, your ticket, and how much of your volume is urgent versus price-shopping. Anyone promising a fixed return is selling, not calculating.