Cisco Catalyst 3850 Switches Support Ended in 2025.
Next Step: Risks, Replacements & Cashback Options.
The Cisco Catalyst 3850 series has been essential for enterprise campus networks in the UK for nearly a decade. However, Cisco has announced that most models will reach their End of Support (EOSL) on 31 October 2025.
After this date, organisations that continue to use Catalyst 3850 switches will face higher security risks, decreased reliability, and possible compliance issues.
At Flux IT Hardware, we assist organisations at every step of Cisco’s hardware lifecycle, from EOSL planning and third-party maintenance to hardware replacement and IT equipment cashback.
Related guide: What Cisco EOSL Means for Your Network in 2026
What Does End-of-Support Mean for the Catalyst 3850?
When a Cisco switch reaches End of Support, Cisco will stop providing:
❌ Security vulnerability patches
❌ IOS XE bug fixes or software updates
❌ SmartNet hardware replacement
❌ TAC technical support
For industries such as finance, education, healthcare, manufacturing, and the public sector, using unsupported network infrastructure can also pose audit and regulatory risks.
Cisco C3850 Lifecycle
End of Sale and End of Life for the Cisco Catalyst 3850 Copper Switches
- End of Life: October 31, 2019
- End of Sale: October 30, 2020
- End of SW Maintenance Release: October 30, 2021
- End of Vulnerability/Security Support: October 31, 2025
- Last Day of Support: October 31, 2025
End of Sale and End of Life for the Cisco Catalyst 3850 Fibre Switches
- End of Life: April 30, 2021
- End of Sale: April 30, 2022
- End of SW Maintenance Release: April 30, 2023
- End of Vulnerability/Security Support: April 30, 2027
- Last Day of Support: April 30, 2027
If you’re unsure which Catalyst 3850 models are installed across your estate, Flux IT can help perform a hardware audit and lifecycle assessment.
Cisco Catalyst 3850 Replacement Options
ℹ️ Did you know? Backward compatibility with many of the C3850’s power supplies and uplink modules is a major benefit of switching from the C3850 series to the most recent Cisco Catalyst 9300 series. Because of this compatibility, users can save a lot of money by upgrading to a C9300 switch and reusing existing parts from their C3850. The compatible parts between the two-switch series are listed in the table below. Users may find the transition easier and have fewer reservations about embracing the newer technology thanks to this compatibility.
Other Benefits of Upgrading:
- Publicly available software downloads.
- Increased performance, enhanced security, and the latest software upgrades from the OEM.
- Current Gen C9300 – no EOL dates announced yet.
| WS-C3850 | C9300 | |
| C3850-NM-4-1G | ✔ | ✔ |
| C3850-NM-2-10G | ✔ | ✔ |
| C3850-NM-4-10G | ✔ (48-port, XS, and mGig) | ✔ |
| C3850-NM-8-10G | ✔ (XS and mGig) | ✔ |
| C3850-NM-2-40G | ✔ (XS and mGig) | ✔ |
| C9300-NM-4G | x | ✔ |
| C9300-NM-4M | x | ✔ |
| C9300-NM-8X | x | ✔ |
| C9300-NM-2Q | x | ✔ |
| C9300-NM-2Y | x | ✔ |
| PWR-C1-350WAC | ✔ | ✔ |
| PWR-C1-350WAC-P | x | ✔ |
| PWR-C1-715WAC | ✔ | ✔ |
| PWR-C1-715WAC-P | x | ✔ |
| PWR-C1-1100WAC | ✔ | ✔ |
| PWR-C1-1100WAC-P | x | ✔ |
| PWR-C1-1900WAC-P | x | ✔ |
| PWR-C1-1900WHV-T | x | ✔ |
| PWR-C1-440WDC | ✔ | x |
| PWR-C1-715WDC | x | ✔ |
| PWR-C3-750WAC-F | ✔ (48XS models) | x |
| PWR-C3-750WAC-R | ✔ (48XS models) | x |
| PWR-C3-750WDC-F | ✔ (48XS models) | x |
| PWR-C3-750WDC-R | ✔ (48XS models) | x |
Risks of Running Catalyst 3850 Switches After 2025
⚠️ No security updates
⚠️ Increased risk of cyber-attacks
⚠️ No OEM support during outages
⚠️ Compliance and audit failures
⚠️ High emergency replacement costs
Having a planned lifecycle strategy is always cheaper and safer than responding to a failure.
Why Flux IT Hardware?
✔ Cisco specialists (enterprise & data centre)
✔ Large UK & EU stockholding
✔ TPM, resale, buy-back & recycling under one roof
✔ Fast response for EOSL-driven projects
✔ Sustainability-focused IT lifecycle management
We work within or outside the traditional Cisco channel, depending on what fits your organisation best.
Make use of Flux IT hardware knowledge.
Speak to the team today on 03330 048885
Frequently Asked Questions
Most Catalyst 3850 models reach the end of support on 31 October 2025, after which Cisco will no longer provide security updates or hardware support.
Yes, but without OEM support. Many organisations use third-party maintenance to safely extend service life.
Cisco recommends the Catalyst 9300 series, though refurbished hardware or TPM may be more cost-effective depending on your environment.
Yes. Widely deployed models like the 3850 often retain strong secondary-market value.
Absolutely — Flux IT supports hybrid estates combining OEM support, TPM, refurbished, and new hardware.
The Cisco C9200-NM-4X and C9300-NM-8X are among the most popular options for organisations upgrading from 1G fibre uplinks to 10G SFP+ connectivity.