Semtech has released AirLink OS 6.0.0, a major new firmware version built exclusively for the new AirLink EX400 and RX400 5G RedCap routers. This isn’t just a point release — it’s the foundation for Semtech’s next generation of AirLink OS-powered industrial and commercial IoT routers, introducing a redesigned user interface, smarter cellular management, enhanced VPN configuration, and dozens of bug fixes that improve day-to-day reliability.
Whether you’re deploying the EX400 in a retail environment, the RX400 at a remote utility substation, or managing a fleet of either across distributed sites, AirLink OS 6.0 delivers meaningful improvements you’ll notice from the moment you log in. Let’s walk through what’s new and why it matters.
Table of Contents
- Behavior Changes to Be Aware Of
- Smarter Cellular Management and SIM Intelligence
- Redesigned User Interface for Easier Navigation
- VPN and Networking Improvements
- Template and Fleet Management Enhancements
- ALMS Remote Management Upgrades
- Power Management Reorganization
- Key Bug Fixes Worth Knowing About
- Known Issues to Watch For
- EM8695 Radio Module Firmware Versions
- Should You Upgrade?
Behavior Changes to Be Aware Of
Before diving into new features, there are a few default behavior changes worth noting — especially if you’re building templates or have standardized deployment configurations.
WAN Policy Link Validation is no longer enabled by default (effective in 6.0.0). This change was made because the previous default caused excessive cellular interface restarts in some deployments. If you rely on link validation, you’ll want to explicitly enable it in your configuration going forward.
Two additional changes are coming in future releases: Wi-Fi Client Isolation will default to Enabled in version 7.0.0, and SMS Provisioning on the EX400 will default to Disabled in version 6.1.0 (it’s already disabled by default on the RX400 as of 6.0). Neither requires immediate action, but they’re worth keeping on your radar if you use those features.
Smarter Cellular Management and SIM Intelligence
The cellular improvements in AirLink OS 6.0 reflect a clear focus on reducing manual intervention and improving resilience in the field — exactly what you need when routers are deployed at remote, unmanned sites.
Multi-Profile SIM Automation
One of the standout additions is native support for multi-profile SIM cards. When the active profile changes on a multi-profile SIM, AirLink OS can now automatically update the radio module firmware image if needed. This means your router can transition between carrier profiles without requiring a technician to manually push firmware — a big deal for organizations managing large fleets of routers across different carrier networks or geographic regions.
Band 8 Disable Option
A new setting lets you disable Band 8 (B8 for 4G LTE, N8 for 5G SA) from being used for network connections. This is useful in deployments where Band 8 causes interference issues or where you want to force the router onto specific bands for performance optimization.
Data Connection Timeout for Auto SIM Switching
AirLink OS 6.0 adds a “Data Connection” timeout trigger to the Auto SIM switching feature. If a cellular interface gets stuck in a “Connecting” state, the router will now automatically switch to an alternate SIM card after a configurable timeout period. Previously, a stuck connection state could leave a router offline until someone manually intervened — not ideal when your router is on a utility pole 50 miles from the nearest technician.
Enhanced Cellular Status Information
Under Status > System > Cellular, you can now view additional details including SIM card EID (also visible in the SIM Database), NSSAI, and Mapped NSSAI. These additions provide better visibility into how your router is interacting with the carrier network, which is especially helpful when troubleshooting 5G SA connectivity or network slicing configurations.
Redesigned User Interface for Easier Navigation
AirLink OS 6.0 brings a significant overhaul to the router’s web management interface. If you’ve worked with previous versions, you’ll notice the improvements immediately.
Enhanced Search
The search function has been meaningfully upgraded. Keywords can now be entered in any order, you can search by both label and value, and there’s now a search history feature. If you’ve ever struggled to find a specific setting buried deep in the configuration menus, this alone is worth the upgrade.
Better Organization and Navigation
Pages have been split into smaller sections under separate tabs, and the left navigation bar now includes icons and collapsibility. There are also new “Expand All/Collapse All” and “Show More/Show Less” controls for configuration menus, plus quick-navigation links between related configuration and status pages. The overall effect is a cleaner, more intuitive interface that requires less scrolling and fewer clicks to get where you need to go.
Visual Feedback and Live Status
A welcome quality-of-life addition: color-coded status indicators. When a value changes on the device, the corresponding field flashes orange for half a second to draw your attention. Time-sensitive data like GPS location now shows current “live” values in green text and stale values in red — a location value is considered stale after a location fix is lost for two or more seconds. This kind of at-a-glance feedback makes monitoring much more intuitive.
Drag-and-Drop Configuration
Configuration items like IP/Network entries can now be reordered via drag and drop, and each item has its own menu with copy, edit, and delete options. These small workflow improvements add up quickly when you’re managing complex configurations.
Other UI Changes
The “Status/Monitoring” section has been renamed simply to “Status.” Audible alerts for notifications have been removed. The Notifications button has been renamed from “CLEAR” to “CLEAR ALL” with individual “Acknowledge” tooltips for each alert. AirLink OS also now uses three-digit version numbers (major.minor.patch) for better readability.
VPN and Networking Improvements
Structured IPsec VPN Configuration
When configuring IPsec VPN tunnels, you can no longer manually enter IP addresses or FQDNs for Peers, Local Subnets, Remote Subnets, Exempt Subnets, and Secondary Peer for Failover. Instead, you select pre-configured IP/Network, FQDN, or Zone objects — or create them directly from the tunnel configuration menu. This structured approach reduces configuration errors and makes templates more portable across devices.
Forced UDP Encapsulation for IPsec
A notable fix addresses IPsec tunnels that weren’t using UDP encapsulation when both endpoints had routable IP addresses (no NAT between them). AirLink OS 6.0 adds an option to force UDP encapsulation, and “Force” is the new default. This resolves connectivity issues that could occur in direct-IP deployments.
Networking Terminology Update
Multi-WAN System Policies have been renamed to remove legacy ALMS references. For example, “ALMS Management Servers” is now “AirLink Management Servers IPv4.” Management and Software Server references can now originate from either ALMS or AMM, depending on your Device Management configuration.
Wi-Fi Terminology Update
The Wi-Fi “Broadcast SSID” setting has been renamed to “Hide SSID.” The underlying functionality and default behavior remain the same — it’s just a clearer label that better describes what the setting actually does.
Template and Fleet Management Enhancements
For anyone managing fleets of routers, the template improvements in 6.0 are significant.
Apply a Replace Template
The Template menu now includes an “Apply a replace template” option. When you apply a replace template (intended for templates created using “Create template from current configuration”), it replaces all settings on the target device with the template’s configuration. Non-default settings in the template modify those settings on the target device, and all other settings revert to factory defaults.
Important note: When applying a replace template via a local connection, the admin password resets to the default password shown on the device label, since templates don’t contain admin passwords. Plan accordingly if you’re using this feature in the field.
ALMS Remote Management Upgrades
Several improvements make remote management through ALMS more capable:
- Remote Troubleshooting Package retrieval — The Troubleshooting Package, which was previously only available when locally connected to the router, can now be retrieved directly through ALMS. This is a major time-saver for distributed deployments where sending a technician on-site just to pull diagnostic logs is impractical.
- NMEA log retrieval — You can now download NMEA location logs through ALMS for GPS-related troubleshooting.
- Improved software updates — The firmware update interface in ALMS now supports searching by both name and release version, and displays a “Processing Software Update” notification while the operation is in progress.
- Fast-Changing Rule workflow change — After clicking the cloud icon to add a data point, you now must explicitly activate the rule and add the data point. The rule no longer auto-activates, giving you more control over when monitoring changes take effect.
Power Management Reorganization
The System > MCU section has been reorganized. Voltage Threshold and Power Management settings, previously in separate areas, are now consolidated into a single System > Power Management section with a Standby Mode subsection and a structured Triggers table. This is especially relevant for the RX400, where power efficiency is a key selling point for solar-powered and battery-backed deployments.
Key Bug Fixes Worth Knowing About
AirLink OS 6.0 addresses a substantial list of bugs across nearly every subsystem. Here are the ones most likely to impact real-world deployments:
Cellular
- Auto-SIM switching now works consistently in all scenarios — previously it could fail under certain conditions.
- Fixed incorrect temperature logging for virtual cellular interfaces.
- Virtual APN interfaces now correctly use the configured APN from the SIM Template database instead of reverting to a previous APN.
Networking
- Multi-WAN priority changes now properly transition the active connection to the higher-priority interface.
- IP Passthrough subnet fix — Previously, enabling IP Passthrough always created a /24 subnet regardless of your configured prefix length. This is now fixed.
- IP Passthrough now handles cellular provider-initiated disconnects more gracefully, resolving intermittent disconnection issues.
- USBNet (USB-as-network-interface) stability improvements — high-speed traffic no longer causes the interface to drop on Windows PCs.
- WAN Policy Link Validation no longer causes excessive cellular interface restarts.
- Network Watchdog link validation now works correctly when configured without an IPv4/IPv6 FQDN/IP host.
Wi-Fi
- Wi-Fi client security mode now displays the actual negotiated mode rather than the configured mode.
- RADIUS authentication failover from primary to secondary server now works reliably.
- Wi-Fi client properly connects to higher-priority IPv6 Access Points.
- DFS channel logging now includes the “Channel Available Check (CAC) complete” message.
VPN
- IPsec tunnels now properly use UDP encapsulation even without NAT between endpoints (Force is the new default).
- FIPS mode IPsec tunnels no longer restart continuously when Multi-WAN policy is configured.
- Dashboard now shows complete and current VPN tunnel status per WAN interface.
Other Notable Fixes
- Ethernet non-default link speed settings now persist across reboots.
- Simple Captive Portal now passes both IPv4 and IPv6 traffic after dual-stack client authentication.
- Router operations (Reboot, Reset, Software Update) are now blocked when unsaved configuration changes exist, preventing accidental loss of changes.
- Template creation with DHCP Relay configuration now properly includes the IPv6 Address field by default.
- NMEA log downloads are now available whenever logs are present on the device, regardless of whether NMEA Logging is currently enabled.
Known Issues to Watch For
No firmware release is perfect, and Semtech has documented several known issues you should be aware of before deploying:
Cellular
- Some carriers allow network connection regardless of APN validity but block data traffic on unauthorized APNs. Always verify you’re using the correct carrier-approved APN.
- Multiple IPv6 addresses via SLAAC/DHCPv6 are not supported — only the last assigned address will be used.
- There’s a known issue where a radio disconnected from 5G may incorrectly report NR5G (NSA) with a 5G band while actually connected to LTE.
Networking
- SNAT rules are not applied on LAN-side interfaces. This also affects container applications where outbound traffic uses the container’s internal IP instead of the router’s LAN IP.
- IPv6 DNS Propagate fails for Ethernet WAN — manually configured DNSv6 servers aren’t propagated to LAN hosts.
- DDNS passwords containing special characters don’t parse correctly, causing DDNS to fail.
VPN
- IPsec tunnels may fail when passing bidirectional Multi-APN traffic both through and outside the tunnel.
- OpenVPN tunnel names cannot include spaces (underscores and hyphens are fine).
- Minimum VPN failover time is approximately 48 seconds regardless of DPD timeout settings.
- IPv4 IPsec VPN over cellular doesn’t work after IPv6 CLAT is enabled.
Templates
- Templates generated locally don’t include the admin password.
- Templates from ALMS may include some default values that local templates exclude.
- QoS Traffic Classifier must be manually selected when creating templates — it’s not auto-included with Bandwidth Policy.
Wi-Fi
- Applying a CSV template with an AP password via ALMS produces a “Bad data type” error. Set AP passwords directly through ALMS as a workaround.
- The Wi-Fi LED may occasionally flash blue and red (instead of purple) when AP mode is enabled with no connected clients.
- Wi-Fi LAN to Wi-Fi WAN throughput may be lower than expected — configure channel separation as wide as possible.
EM8695 Radio Module Firmware Versions
AirLink OS 6.0 ships with the following carrier-specific radio firmware:
- AT&T: 01.01.01.00
- Generic: 01.01.01.00
- T-Mobile: 01.01.01.00
- Verizon: 00.01.16.00
Should You Upgrade?
If you’re deploying or already running the AirLink EX400 or RX400, AirLink OS 6.0 is the firmware these routers ship with and the platform they’re built for. The combination of smarter cellular management (especially the multi-profile SIM automation and Auto SIM timeout), the redesigned UI, remote troubleshooting package retrieval via ALMS, and the extensive list of networking and VPN bug fixes makes this a solid foundation.
It’s worth noting that AirLink OS 6.0 is exclusive to the EX400 and RX400 — it does not apply to the XR90, XR80, XR60, or RX55. Those routers continue on their existing AirLink OS release tracks.
Semtech has also indicated that many of the capabilities introduced in 6.0 will extend to additional AirLink OS devices in the upcoming 6.1 release, so this is setting the stage for a broader platform evolution.
Need Help with Your AirLink Deployment?
At 5Gstore.com, we sell and support Semtech (Sierra Wireless) AirLink routers and can help with firmware updates, configuration, antenna selection, and deployment planning. Whether you’re migrating from an RV55 or deploying a new fleet of RX400 routers, contact our team for expert assistance.
