KPN Mobile Core Migration – Phase 3 Overview

This article explains what to expect during Phase 3 of the KPN mobile core network upgrade.

These changes are only relevant for customers using KPN SIMs.

If your devices do not use KPN SIMs, you can safely disregard this information.
 

Why this change is happening

KPN is upgrading its mobile core network to improve performance, stability, and network resilience.

Phase 3 focuses on migrating data services to KPN’s new infrastructure.

These changes will help reduce downtime risk, simplify IP management, and prepare the network for future growth.

This migration is part of a mandated network transformation programme and must be completed before 31 March 2026.
 

When the migration is happening and what is the impact

Phase 3 is being carried out on an APN-by-APN basis. This phased approach helps minimise risk and ensures network behaviour is validated as the rollout progresses.

Customers may experience a temporary service interruption of approximately 10–30 minutes per APN while the work is carried out.

Devices should automatically reconnect within a few seconds or minutes after migration. If a device does not recover automatically, a manual reboot may be required.

The planned migration schedule is outlined below. Customers will receive advance communications ahead of their specific migration window by on their APNs, including confirmation of timings and any expected service impact.

Planned migration schedule by APN:

arkessa.com
Completed

arkessahd.com
4^th March 2026 - 19:30 UTC.

wlapn4.com
Completed

wlapn.com
Validation testing begins March 2026, with full migration planned shortly thereafter. This will be the final APN to transition as part of Phase 3. Further details, including confirmed timings, will be shared with customers in advance.
 

wlapn.com Validation Testing

Due to the scale of the wlapn.com migration and the IP addressing changes involved, We are conducting controlled validation testing before the full migration.

• One active SIM will be migrated to the new core as a test.

• Customers will be notified directly of the SIM and migration date.

• Customers must monitor the SIM and confirm whether it continues to operate as expected.

If the test SIM operates correctly:

• The remaining SIM estate will be marked as ready for migration.

If issues occur:

• Configuration changes will be required before proceeding.

Customers with fewer than 50 SIMs will move directly into the main migration phase.

Full Migration and Provisioning Freeze (wlapn.com)

Once validation testing is complete, the full migration of wlapn.com will take place in batches over approximately one week.

During the main migration window (approximately 48 hours), a temporary provisioning freeze will apply to the wlapn.com APN.

During this period, you will not be able to:

• Activate new SIMs

• Bar or unbar SIMs

• Cancel SIMs

• Modify Voice, APN, or SMS services

• Change roaming configurations
   

What is changing

Improved network resilience

• KPN is introducing automated failover across multiple gateways, replacing the old manual failover setup.
• This will help reduce the risk of downtime and improve continuity of service.

Fixed IP addressing changes

• Devices will no longer retain a fixed IP address at the device level.
• Instead, each device will now receive a private dynamic IP.
• KPN will apply an IMSI-based NAT function, which ensures that:
  • The external-facing IP (seen by backend systems) remains unchanged.
  • The local IP seen by the device will now differ, this is expected and correct.
     

Why this matters for your configuration

If your device or application is hardcoded to expect a fixed SIM IP, it will no longer connect correctly after migration.

Common examples include:

• VPN tunnels that use a static SIM IP as the source address.
• Applications or servers that reference a fixed SIM IP directly.

👉 For detailed step-by-step guidance on how to check your configuration and remove any hardcoded IPs, see:

• Ensuring Your Teltonika Routers with KPN SIMs Do Not Use a Hardcoded IP Address
• Ensuring Your Devices with KPN SIMs Do Not Use a Hardcoded IP Address
   

What you need to do

To avoid any disruption during or after the migration, please review your setup now:

• ✅ Check whether a fixed SIM IP is hardcoded in your device or application logic. If so, it must be removed.
  • For help, see: 
    • Ensuring Your Teltonika Routers with KPN SIMs Do Not Use a Hardcoded IP Address
    • Ensuring Your Devices with KPN SIMs Do Not Use a Hardcoded IP Address
• ✅ Ensure all devices use DHCP (dynamic IP assignment).
• ✅ If using IPSec VPNs, set the source IP as the WAN interface, not a static SIM IP.
• ✅ Be prepared to reboot devices if they do not automatically reconnect after migration.

Updating configurations now will help you avoid unnecessary downtime and ensure a smooth transition.
 

Understanding the new IP behaviour

After migration, you may notice that the IP address displayed in SIMPro is different from the IP address visible on your device.

This is intentional and caused by KPN’s IMSI-based NAT function:

• The device receives a private dynamic IP locally.
• The backend system continues to recognise the same external-facing IP.

What happens if you do nothing

If a fixed IP remains hardcoded in your device or application, it may:

• Fail to reconnect automatically after migration.
• Be unable to establish VPN tunnels.
• Stop sending or receiving data.

To prevent this, please confirm your devices are correctly configured before the migration takes place.
 

Support and further information

• You will receive planned maintenance notifications before your specific migration window.
• Real-time updates will also be available via the SIMPro MNO Outages page.
• Our Network Operations Team is available to provide guidance on reviewing or updating your setup at support@wirelesslogic.com.
• For Enterprise customers, our Care team will provide direct support throughout the transition.

If you have any questions or need help, please contact support@wirelesslogic.com or your account manager.