September 30, 2026: The Worst Deadline Day of the Quarter
Twenty-nine days from now, four vendors' clocks stop on the same day — and none of them coordinated it. On September 30, 2026: Microsoft retires Project Online outright (the service stops existing, and Microsoft's guidance is to back up your data first); FortiOS 7.2 reaches end of support on the internet-facing firewall OS with the deepest KEV history on our books; SonicWall's SonicOS 7.3.0, 7.3.1, 7.3.2 and the 7.0.1-5169 build all reach end of support at once; and ten Azure services and APIs — Azure Virtual Desktop (Classic) and three generations of Service Bus control-plane APIs among them — retire. Azure Functions apps still on the v3 runtime in Linux Consumption plans stop running after the same date.
The cluster, in one table
| What | Vendor | What happens Sep 30 |
|---|---|---|
| Project Online | Microsoft | Retirement — service stops; data unreachable after the date |
| FortiOS 7.2 | Fortinet | End of support: Sep 30, 2026 |
| SonicOS 7.3.0 / 7.3.1 / 7.3.2 | SonicWall | End of support: Sep 30, 2026 (upgrade path: 7.3.3+) |
| SonicOS 7.0.1-5169 | SonicWall | End of support: Sep 30, 2026 |
| 10 Azure services & APIs | Microsoft | Retirements — the full September table |
| Azure Functions v3 on Linux Consumption | Microsoft | Apps stop running after Sep 30 |
Triage order for the 29 days
1. Retirements first — they are the only items on the list where something stops working. Export Project Online data, migrate the Azure dependencies, and check for Functions v3 apps on Linux Consumption plans (that one halts applications, not support).
2. The edge platforms second — FortiOS 7.2 and the SonicOS releases are internet-facing firewall software; past end of support, every new vulnerability is permanent, and both platforms carry CISA KEV history. Both are tracked line-by-line on our EOS Edge Device List, alongside the rest of the device class CISA's BOD 26-02 covers.
3. Then the audit — if these four surprised you, others will: paste an inventory into the Stack Scanner, or put your stack on deadline alerts and let the 365/90/60/30/7/0-day warnings do the calendar-watching.
Frequently Asked Questions
What reaches end of support or retires on September 30, 2026?
On one day: Microsoft Project Online retires entirely; FortiOS 7.2 reaches end of support; SonicOS 7.3.0, 7.3.1, 7.3.2 and the 7.0.1-5169 build reach end of support; and ten Azure services and APIs retire. Azure Functions apps on the v3 runtime in Linux Consumption plans stop running after the same date.
Why do so many deadlines land on September 30?
Quarter-end and fiscal-year-end gravity — vendors align lifecycle milestones to quarter boundaries, and September 30 closes both Q3 and the US federal fiscal year. The pile-up is accidental, which is why per-product tracking from vendors' own lifecycle pages beats any single roll-up.
Which of these deadlines is hardest?
The retirements — end-of-support software keeps running unpatched, but Project Online stops existing along with access to its data, and retired Azure APIs stop answering. Among the EOS items, FortiOS 7.2 stands out for its exploitation history.
Related
- The EOS Edge Device List — every edge platform's end-of-support status, machine-readable
- Project Online retires September 30 · the Azure September table
- End of support & the CISA BOD 26-02 clock
- The 2026 EOL calendar — the whole year's deadlines