Cisco ISR 3900 Series Replacement — What Cisco Recommends
Cisco support for the Cisco ISR 3900 Series ended Dec 2022 — unsupported units need a plan. Cisco's own end-of-life bulletin names the successor below — quoted from the source, with the successor's live support status where EOSL.ai tracks it.
The Cisco-named replacement
per-part mapping in the bulletin (9 replacement parts listed) — named in the Cisco EOL bulletin ↗ as the migration path.
C1-CISCO4431 is not yet tracked on EOSL.ai — no vendor end-of-life notice has been captured for it, which is typical of current products.
Cisco ISR 3900 Series lifecycle dates
| SKU group | End of sale | EOSL / last support | Source |
|---|---|---|---|
| Switch hardware | Dec 2017 | Dec 2022 | bulletin ↗ |
Per-part-number replacement mapping (21)
As listed in the Cisco bulletin's migration table for each part number.
| End-of-life part | Description | Bulletin-listed replacement |
|---|---|---|
| C1-CISCO3925 | C1-CISCO4431 | |
| C1-CISCO3925E | C1-CISCO4431 | |
| C1-CISCO3945 | C1-CISCO4431 | |
| C1-CISCO3945E | C1-CISCO4431 | |
| C3925-AX | ISR4431-AX | |
| C3925-AXV | ISR4431-AXV | |
| C3925-CME-SRST | ISR4431-V | |
| C3925-VSEC-CUBE | ISR4431-VSEC | |
| C3925-VSEC | ISR4431-VSEC | |
| C3925E-AX | ISR4431-AX | |
| C3925E-CME-SRST | ISR4451-X-V | |
| C3925E-VSEC-CUBEK9 | ISR4451-X-VSEC | |
| C3925E-VSEC | ISR4451-X-VSEC | |
| C3945-AX | ISR4431-AX | |
| C3945-AXV | ISR4451-X-AXV | |
| C3945-CME-SRST | ISR4431-V | |
| C3945-VSEC-CUBE | ISR4451-X-VSEC | |
| C3945-VSEC | ISR4431-VSEC | |
| C3945E-AX | ISR4451-X-AX | |
| C3945E-CME-SRST | ISR4451-X-V | |
| C3945E-VSEC-CUBEK9 | ISR4451-X-VSEC |
Migration questions
What is the replacement for the Cisco ISR 3900 Series?
Cisco's end-of-life bulletin names C1-CISCO4431 as the recommended migration path for the Cisco ISR 3900 Series. The exact wording and any per-part-number mapping are in the linked bulletin.
Is the Cisco ISR 3900 Series end of life?
Cisco support for the Cisco ISR 3900 Series ended Dec 2022 — unsupported units need a plan. Full lifecycle dates by part number: https://eosl.ai/system/cisco-isr-3900/.
Is there a per-part-number replacement mapping for the 3900 Series?
Yes — the bulletin maps replacements at the part-number level for 21 SKUs (for example C1-CISCO3925 → C1-CISCO4431). The full table is on this page.
Do I have to buy the Cisco-recommended replacement?
No. The bulletin's named successor is Cisco's suggested path, not an obligation. Teams also keep 3900 Series units running under third-party maintenance after the support cutoff, migrate to a different vendor, or run low-criticality units to failure with the risk documented. See the support-options guide for the trade-offs.