3CX Version 20 Upgrade Guide | System Requirements & One.Console

3CX Version 20 Upgrade : Minimum Requirements, Checklist & One.Console Guide


Upgrading to 3CX Version 20 (V20) is a major step forward for partners and businesses using 3CX unified communications. To ensure a smooth migration from 3CX Version 18 to Version 20, it’s essential to meet the latest system requirements and follow the official upgrade checklist.
If your infrastructure doesn’t meet the updated specifications, the upgrade will abort during pre-check. This guide outlines the minimum requirements, recommended resources, and action steps for a successful transition.

Why Upgrade to 3CX Version 20?

3CX V20 introduces:

  • A modernized Debian 12 base
  • Improved security and performance
  • New Departments feature for call routing
  • Better management and scalability
For MSPs, VARs, and resellers across Canada, USA, and Australia, upgrading ensures your clients stay on a supported, secure, and future-ready platform. Need help ? Contact support@telin.com 


Minimum System Requirements for 3CX V20 Upgrade

Before starting the upgrade, verify that your current server or VM meets the following minimum hardware and system requirements:

  • CPU / vCores: 2 vCPUs (cores)

  • RAM: 2 GB minimum (4 GB recommended for larger deployments)

  • Disk Space: At least 5 GB free on the system partition

  • Operating System: Debian 12 (Linux preferred)

  • Split DNS: Must be configured correctly

  • Clean Environment: No unauthorized apt sources or third-party packages that interfere with Debian updates

⚠️ Note: Servers with 1 CPU and 1 GB RAM will fail the upgrade. Scale resources before attempting the transition. Follow instruction o how to upgrade your server in One.Console 

For partners managing multi-tenant 3CX hosting, call centers, or enterprise deployments, we recommend:

  • 4 vCPUs or higher

  • 4–8 GB RAM

  • 20 GB+ free storage

  • Redundant connectivity (SD-WAN, MPLS, or Peplink One.Demarc)

This ensures reliability, minimal downtime, and faster recovery in case of issues.

3CX V20 Upgrade Checklist

Follow this step-by-step process to reduce upgrade risks:

  1. Validate Current Resources – Check RAM, CPU, and disk space.

  2. Scale Up if Needed – Adjust your VM or hardware to meet requirements.

  3. Verify Split DNS – Internal and external DNS must resolve correctly.

  4. Clean the Server – Remove unused apt sources and conflicting packages.

  5. Backup Your System – Create a full 3CX V18 backup before upgrading.

  6. Run the Upgrade – Initiate from the 3CX Management Console.

  7. Post-Upgrade Review – Reconfigure departments, call flows, and user permissions.

Common Upgrade Issues (and How to Avoid Them)

  • Upgrade Aborts at Pre-Check: Usually caused by insufficient CPU/RAM.

  • DNS Failures: Misconfigured split DNS leads to registration errors.

  • Debian Source Errors: Extra apt sources interfere with upgrade scripts.

Tip: Always run upgrades on a test environment first, especially if hosting multiple tenants.

TELIN Partner Support for 3CX V20

At TELIN, we help MSPs, resellers, and 3CX partners across North America and Australia with:

  • Pre-upgrade readiness checks

  • Resource scaling and migration support

  • SLA-backed hosting (One.PaaS / One.IaaS)

  • SIP trunking with global redundancy (One.Voice)

  • Post-upgrade troubleshooting

Upgrading to 3CX Version 20 doesn’t have to be stressful. TELIN ensures a seamless transition with minimal downtime so you can stay focused on your customers.

Upgrade Steps from the Telin One.Console

Not yet a partner? 
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Step 1: Access the Telin One.Console.

TELIN partners can perform the resource upgrade and migration seamlessly via the One.Console portal. Not yet a partner, register now!




Step 2: Select the new specs.

Upgrade CPU and RAM to meet the new 3CX V20 requirements.





Estimated downtime is 15-20 minutes

Step 3: Proceed with the upgrade.

  • Once the resource upgrade is complete, continue with the 3CX Version 20 upgrade process.

TELIN Partner Support for 3CX V20

At TELIN, we help MSPs, resellers, and 3CX partners across North America and Australia with:

  • Pre-upgrade readiness checks

  • Resource scaling and migration support

  • SLA-backed hosting (One.PaaS / One.IaaS)

  • SIP trunking with global redundancy (One.Voice)

  • Post-upgrade troubleshooting

Upgrading to 3CX Version 20 doesn’t have to be stressful. TELIN ensures a seamless transition with minimal downtime so you can stay focused on your customers.

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