Short version: The Cisco ISR 4000 series is end-of-sale. The ISR4200, ISR4300 and most of the ISR4400 line stopped shipping on February 6, 2024, with a Last Date of Support of November 30, 2028. The ISR4461 is on a separate, later bulletin — last ship April 20, 2025, LDoS January 31, 2030. And the ISR G2 generation before it — the 2900 and 3900 — went fully obsolete on December 31, 2022.
If you migrated 2900s to ISR 4000s a few years ago, you migrated onto a platform that is now itself end-of-sale. This guide has the real milestone tables from Cisco's bulletins, the SKU-for-SKU replacement map to the Catalyst 8000, and the module trap that makes this migration more expensive than it looks.
The module trap — read this before you budget
Start here, because it changes the number.
Cisco's own ISR4461 bulletin states it plainly: "all C-NIM- and C-SM- modules are exclusively supported on the Catalyst 8000 Series Platforms and are not compatible with the ISR 4000 Series platforms."
The replacement modules are a new part family. Your existing NIM and SM-X inventory does not move forward, and the new Catalyst modules do not move backward into ISR chassis. That means a phased, chassis-by-chassis migration where you reuse module inventory across a mixed estate does not work. You are replacing chassis and modules together, per site.
Here is the module map Cisco publishes:
| ISR 4000 module | Description | Catalyst 8000 replacement |
|---|---|---|
| NIM-1GE-CU-SFP / NIM-2GE-CU-SFP | 1- and 2-port GE WAN NIM, dual-mode RJ45 & SFP | C-NIM-2T (2-port 1GE SFP with MACsec) |
| SM-X-4X1G-1X10G | 4-port GE/SFP or 1-port 10G SFP+ | C-NIM-4X (4-port 10G SFP/SFP+) |
| SM-X-6X1G | 6-port dual-mode GE / SFP | C-NIM-4X |
| SM-X-16G4M2X | 16-port 1G, 4-port 2.5G mGig, 2-port 10G SFP/SFP+ | C-SM-16P4M2X |
| SM-X-40G8M2X | 40-port 1G, 8-port 2.5G mGig, 2-port 10G SFP/SFP+ | C-SM-40P8M2X |
| SM-X-NIM-ADPTR | SM-X adapter for one NIM module | C-SM-NIM-ADPT |
| NIM-SSD | NIM carrier card for SSD drives | SSD-M2SED-600G (M.2 SED 600G for 8200/8300/8500L) |
Note the MACsec on the C-NIM-2T. That is not a like-for-like swap; it is an upgrade you are paying for whether you wanted it or not.
ISR 4200 / 4300 / select 4400 — the main bulletin
Cisco bulletin EOL14896. Covers the ISR4221, ISR4321, ISR4331, ISR4351, ISR4431 and ISR4451-X, plus their memory, flash, PSU and licence SKUs.
| Milestone | Date |
|---|---|
| End-of-Life Announcement | November 7, 2022 |
| End-of-Sale (HW, Licence) | November 7, 2023 |
| Last Ship Date | February 6, 2024 |
| End of Routine Failure Analysis | November 6, 2024 |
| End of New Service Attachment | November 6, 2024 — passed |
| End of SW Maintenance Releases | August 31, 2025 |
| End of Service Contract Renewal | February 5, 2028 |
| End of Vulnerability / Security Support | November 30, 2028 |
| Last Date of Support | November 30, 2028 |
The date that quietly matters is End of New Service Attachment: November 6, 2024. It has already passed. If a unit is not already on a support contract, you can no longer put it on one. Buying a used ISR4331 today means buying a router you cannot attach SmartNet to. It can only be maintained on contracts that already exist.
Software: the last supported IOS-XE trains are 17.9.x and 17.12.x. Cisco explicitly states that 17.10.x and 17.11.x will not be supported on these platforms — if you are standardising an image across a mixed fleet, those two trains are off the table. Standard EoVSS support for the 17.12 train runs to September 2027, after which Cisco says ad-hoc security maintenance releases will be made available for ISR 4K until November 2028.
Replacement map
| End-of-sale ISR | Cisco's replacement |
|---|---|
| ISR4221 / ISR4221X | C8200L-1N-4T — Catalyst 8200L, 1 NIM slot, 4× 1G WAN |
| ISR4321 | C8200-1N-4T |
| ISR4331 | C8200-1N-4T |
| ISR4351 | C8300-2N2S-6T |
| ISR4431 | C8300-1N1S-4T2X or C8300-1N1S-6T |
| ISR4451-X | C8300-2N2S-4T2X or C8300-2N2S-6T |
Note the 4331 and the 4321 both collapse onto the same C8200-1N-4T. If you sized a 4331 over a 4321 for the extra SM slot, that slot does not exist on the replacement — you may need to step up to a C8300.
ISR4461 — a different bulletin, later dates
Cisco bulletin EOL15446. This is the one people get wrong, because they assume the whole ISR 4000 line moved together. It did not.
| Milestone | Date |
|---|---|
| End-of-Life Announcement | July 22, 2024 |
| End-of-Sale (HW) | January 20, 2025 |
| Last Ship Date | April 20, 2025 |
| End of SW Maintenance Releases | January 20, 2026 |
| End of Routine Failure Analysis | January 20, 2026 |
| End of New Service Attachment | January 20, 2026 — passed |
| End of Service Contract Renewal | April 17, 2029 |
| End of Vulnerability / Security Support | January 31, 2030 |
| Last Date of Support | January 31, 2030 |
The 4461 buys you 14 more months of support than the rest of the ISR 4000 line — LDoS January 2030 vs November 2028. Its last IOS-XE train is 17.18.x, six trains further along than the 17.12.x ceiling on the 4200/4300/4400.
Replacement for every ISR4461 SKU: C8300-2N2S-4T2X.
The TAA variant ISR4461/K9++ also maps to the C8300-2N2S-4T2X. (The ++ suffix is Cisco's TAA-compliant designation — see our part number decoder for the rest of Cisco's SKU conventions.)
ISR G2: 2900 and 3900 — already obsolete
Both bulletins were announced the same day, September 9, 2016. The 2900 is EOL11158; the 3900 is EOL11157.
| Milestone | Cisco 2900 Series | Cisco 3900 Series |
|---|---|---|
| End-of-Sale | December 9, 2017 | December 9, 2017 |
| Last Ship Date | March 9, 2018 | March 9, 2018 |
| End of SW Maintenance | December 9, 2020 | December 9, 2020 |
| End of Vulnerability / Security Support | December 8, 2020 | September 8, 2020 |
| End of Service Contract Renewal | March 9, 2022 | March 9, 2022 |
| Last Date of Support | December 31, 2022 — passed | December 31, 2022 — passed |
Note the small discrepancy that a summary table would hide: the 3900's security support ended three months earlier than the 2900's — September 8, 2020 vs December 8, 2020 — despite identical announcement, sale and support dates. This is exactly why you read the bulletin for your platform rather than a generation-level summary.
Both are fully obsolete as of the end of 2022. No TAC, no RMA, no software, no contracts. Any 2900 or 3900 still in production is running unpatched IOS with known CVEs and no path to a fix.
Cisco's original migration for these was to the ISR 4000 — 2901→ISR4321, 2911/2921→ISR4331, 2951→ISR4351, 3925/3925E→ISR4431, 3945/3945E→ISR4451-X. Every one of those targets is now itself end-of-sale. If you are still on G2, skip the ISR 4000 entirely and go straight to the Catalyst 8000.
The two-hop cascade, in one table
This is the summary most people actually need — where a G2 router lands today, in one hop rather than two:
| If you still have | Cisco's 2016 answer (now also EOL) | Buy this instead, today |
|---|---|---|
| CISCO2901 | ISR4321 | C8200-1N-4T |
| CISCO2911 / CISCO2921 | ISR4331 | C8200-1N-4T |
| CISCO2951 | ISR4351 | C8300-2N2S-6T |
| CISCO3925 / 3925E | ISR4431 | C8300-1N1S-4T2X / C8300-1N1S-6T |
| CISCO3945 / 3945E | ISR4451-X | C8300-2N2S-4T2X / C8300-2N2S-6T |
Planning notes
New service attachment is closed on the whole ISR 4000 line. This is the constraint that should drive your timeline more than LDoS. For the 4200/4300/4400 it closed November 6, 2024; for the 4461, January 20, 2026. A used ISR 4000 bought today cannot be put under a Cisco support contract. For some organisations that is fine — for anyone with a contractual support requirement, it makes the secondary market a non-option for these SKUs and forces the Catalyst 8000 decision now.
Do not standardise on 17.10.x or 17.11.x. Cisco explicitly excluded both trains from ISR 4000 support. If those are in your golden image plan, the ISR 4000s in the estate will be stranded.
Refurbished units remain available until LDoS. Cisco notes that ISR 4000 hardware may still be purchasable through the Cisco Refresh (certified remanufactured) programme in limited supply, on a first-come-first-served basis, until the Last Date of Support is reached. That is a route to spares — not to a growing estate.
The optics usually do carry over. Unlike the NIM/SM modules, standard SFP and SFP+ optics generally move between platforms. Verify coding before you assume — vendor-locked optics are their own problem, covered in our vendor-coded transceiver guide.
If you are doing a full Cisco refresh
Routers are rarely the only thing on the EOL list. If the ISRs are due, the access layer usually is too:
- Catalyst 3650 & 3850 EOL → Catalyst 9300 migration map
- Catalyst 2960-X & 2960-XR EOL → Catalyst 9200, and the stacking trap
- Juniper EX Series EOL dates (2026 update), if the estate is mixed
Where to source the parts
- Routers — Catalyst 8200 / 8300 for the refresh, ISR 4000 and G2 chassis for the estate you are keeping alive
- Cisco Parts — NIMs, SM-X modules, PSUs (PWR-4430-AC, PWR-4450-AC), flash and DRAM upgrades
- Network Switches — Catalyst 9200 / 9300 if the access layer is going at the same time
- Transceivers & Optics — SFP, SFP+ and QSFP for both platforms
For an ISR 4000 estate you intend to run to LDoS, the parts that strand a router are power supplies and NIM modules, not the chassis. Secure those while supply is deep — and remember that once Cisco stops remanufacturing, the secondary market is the only market.
Buying used Cisco carries its own risks. Our guide on how to buy refurbished Cisco safely covers serial verification and what a legitimate seller should be able to tell you.
Need a quote?
Send us your ISR part number list — G2 spares, ISR 4000 spares, or a Catalyst 8000 refresh with the matching C-NIM/C-SM modules — and we will price it and flag anything past End of New Service Attachment. We ship worldwide DDP with duties included, accept purchase orders, and return quotes within 24 hours.
Sources: Cisco Systems, "End-of-Sale and End-of-Life Announcement for the Cisco ISR4200, ISR4300 and select ISR4400 Series Platform" (EOL14896, amended, updated November 6, 2024). Cisco Systems, "End-of-Sale and End-of-Life Announcement for the Cisco ISR4461 Series Platform" (EOL15446, amended, updated May 9, 2025). Cisco Systems, "End-of-Sale and End-of-Life Announcement for the Cisco 2900 Series Integrated Services Routers" (EOL11158, amended, updated November 17, 2016). Cisco Systems, "End-of-Sale and End-of-Life Announcement for the Cisco 3900 Series Integrated Services Routers" (EOL11157, amended). All milestone dates, part numbers, replacement SKUs, module compatibility statements and IOS-XE train restrictions above are transcribed from these four bulletins. Cisco amends EOL bulletins — confirm against the live bulletin for your exact part number before purchasing.